Solving two-step linear equations using distributive property: a(x + b) = c

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Intros
Lessons
    • What is Distributive Property?
    • How to use distributive property to solve linear equations?
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Examples
Lessons
  1. Solve the equation using model.
    1. 4(x+1)=124\left( {x + 1} \right) = 12
    2. 2(x3)=82\left( {x - 3} \right) = 8
  2. Solve.
    1. 3(x9)=453\left( {x - 9} \right) = 45
    2. 7(10+x)=147\left( {10 + x} \right) = 14
    3. 15=3(x6) - 15 = 3\left( {x - 6} \right)
    4. 22=11(x+13) - 22 = 11\left( {x + 13} \right)
  3. John has a round table with a circumference of 314.16 cm, but it is too big for his new home. So, he cut off a 10 cm wide border around the edge.
    1. Write the equation that represents the situation.
    2. What is the circumference of the table now? Round your answer to two decimal places.
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Practice
Topic Notes
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Distributive property is an algebra property that we use all the time! When you see equations in the form of a(x+b), you can transform them into ax+ab by multiplying the terms inside a set of parentheses. In this section, we will make use of this property to help us solve linear equations.

Introduction to Solving Two-Step Linear Equations with Distributive Property

Welcome to our lesson on solving two-step linear equations using the distributive property! This fundamental skill is crucial for advancing your algebra knowledge. To kick things off, we've prepared an introduction to two-step linear equations video that will give you a clear visual understanding of the concept. This video is an essential starting point, as it breaks down the process step-by-step, making it easier to grasp. As we dive into two-step linear equations, you'll see how the distributive property plays a key role in simplifying expressions. We'll learn to "unpack" terms within parentheses, which is often the first step in solving these equations. Don't worry if it seems challenging at first with practice, you'll become more comfortable applying this property. Remember, mastering this technique will set a strong foundation for more complex algebraic problems in the future. Let's get started on this exciting journey through two-step linear equations!

Understanding the Distributive Property

The Rectangle Area Analogy

The distributive property is a fundamental concept in algebra that can be easily understood using the rectangle area analogy. Imagine a rectangle with length (a + b) and width c. The area of this rectangle can be calculated in two ways, which demonstrates the distributive property in action.

Method 1: Total Area

We can find the total area by multiplying the entire length by the width:

Area = (a + b) × c

Method 2: Sum of Two Smaller Rectangles

Alternatively, we can divide the rectangle into two smaller rectangles:

  • Rectangle 1: length a, width c
  • Rectangle 2: length b, width c

The total area is then the sum of these two smaller rectangles:

Area = (a × c) + (b × c)

The Distributive Property in Action

By equating these two methods, we arrive at the distributive property:

(a + b) × c = (a × c) + (b × c)

This property shows that multiplying a sum by a number is the same as multiplying each addend by that number and then adding the products.

Numerical Example

Let's consider a rectangle with length 5 + 3 and width 4:

  • Method 1: (5 + 3) × 4 = 8 × 4 = 32
  • Method 2: (5 × 4) + (3 × 4) = 20 + 12 = 32

Both methods yield the same result, confirming the distributive property.

Using Variables

The distributive property works with variables too. For example:

(x + y) × z = xz + yz

This allows us to simplify and expand algebraic expressions efficiently.

Simplifying Expressions

The distributive property is crucial for simplifying expressions. For instance:

3(x + 2) can be simplified to 3x + 6

This process "distributes" the 3 to each term inside the parentheses.

More Complex Examples

The distributive property can be applied to more complex expressions:

  • 2(3x + 4y - 5) = 6x + 8y - 10
  • (x + 3)(x - 2) = x² + x - 6

In the second example, we distribute (x + 3) to both terms inside the second parentheses.

Practical Applications

Understanding the distributive property is essential for:

It's a fundamental tool that bridges arithmetic and higher-level mathematics.

Conclusion

The distributive property, illustrated through the rectangle area analogy, provides a visual and intuitive understanding of this important algebraic concept. By mastering this property, students can simplify expressions, solve equations more efficiently, and build a strong foundation for advanced mathematical concepts. Remember, whether working with numbers or variables, the distributive property remains a powerful tool in mathematical problem-solving.

Applying Distributive Property to Equations

Welcome, math enthusiasts! Today, we're going to explore how to use the distributive property to solve equations with variables trapped in brackets. This technique is crucial for tackling two-step equations and freeing those trapped variables. Let's dive in with some practical examples!

First, let's consider the equation: 2(x-3) = 18. This equation might look intimidating at first, but don't worry we'll break it down step by step:

  1. Start by applying the distributive property to the left side of the equation. This means multiplying 2 by both terms inside the parentheses:
    2x - 6 = 18
  2. Now we have a standard two-step equation. Let's add 6 to both sides to isolate the variable term:
    2x = 24
  3. Finally, divide both sides by 2 to solve for x:
    x = 12

See how we freed that trapped variable? The distributive property helped us simplify the equation, making it much easier to solve.

Let's try another example: 5(x+1) = 45. We'll follow the same process:

  1. Apply the distributive property by multiplying 5 by both terms in the parentheses:
    5x + 5 = 45
  2. Subtract 5 from both sides to isolate the variable term:
    5x = 40
  3. Divide both sides by 5 to solve for x:
    x = 8

Great job! You've successfully solved another equation using the distributive property.

Here are some key points to remember when solving equations with trapped variables:

  • Always start by applying the distributive property to eliminate the parentheses.
  • Take your time and work through each step carefully.
  • Remember to perform the same operation on both sides of the equation to maintain balance.
  • Double-check your work by substituting your answer back into the original equation.

Practice is key to mastering this skill. Try solving more equations with trapped variables, gradually increasing the complexity. You might encounter expressions like 3(2x-4) = 24 or 4(x+2) - 2(x-1) = 10. Don't be intimidated apply the same principles we've discussed, and you'll be solving these equations in no time!

Remember, the distributive property is a powerful tool in algebra. It allows us to simplify complex expressions and solve equations that might otherwise seem daunting. As you become more comfortable with this technique, you'll find it opens doors to solving even more challenging problems.

Keep up the great work, and don't hesitate to review these steps whenever you need a refresher. With practice and persistence, you'll become a pro at solving equations with trapped variables using the distributive property. Happy equation solving!

Step-by-Step Guide to Solving Two-Step Linear Equations Using the Distributive Property

Introduction

Solving two-step linear equations using the distributive property is a fundamental skill in algebra. This guide will walk you through the process, providing clear steps and examples to help you master this important mathematical concept.

Step 1: Identify the Equation Structure

Before solving, recognize the structure of a two-step linear equation using the distributive property. It typically looks like this: a(x + b) = c, where 'a' is the coefficient, 'x' is the variable, and 'b' and 'c' are constants.

Step 2: Apply the Distributive Property

Multiply the coefficient 'a' by each term inside the parentheses. This step transforms the equation into a standard two-step linear equation.

Example:

3(x + 2) = 15
Becomes: 3x + 6 = 15

Step 3: Combine Like Terms

If there are any like terms on either side of the equation after applying the distributive property, combine them.

Step 4: Isolate the Variable Term

Move all terms containing the variable to one side of the equation (usually the left) and all constant terms to the other side.

Example:

3x + 6 = 15
Subtract 6 from both sides: 3x = 9

Step 5: Solve for the Variable

Divide both sides of the equation by the coefficient of the variable to isolate it.

Example:

3x = 9
Divide both sides by 3: x = 3

Step 6: Check Your Solution

Always verify your answer by substituting it back into the original equation.

Example:

3(3 + 2) = 15
3(5) = 15
15 = 15 (True)

Additional Examples

Example 1: 2(x - 4) = 10

Step 2: 2x - 8 = 10
Step 4: 2x = 18
Step 5: x = 9
Check: 2(9 - 4) = 10, 2(5) = 10, 10 = 10 (True)

Example 2: 5(2x + 1) = 35

Step 2: 10x + 5 = 35
Step 4: 10x = 30
Step 5: x = 3
Check: 5(2(3) + 1) = 35, 5(7) = 35, 35 = 35 (True)

Example 3: -3(x + 2) = 21

Step 2: -3x - 6 = 21
Step 4: -3x = 27
Step 5: x = -9
Check: -3(-9 + 2) = 21, -3(-7) = 21, 21 = 21 (True)

Common Mistakes to Avoid

Common Mistakes and How to Avoid Them

When solving equations with distributive property, students often encounter challenges that can lead to errors. Understanding these common mistakes and learning how to avoid them is crucial for mastering this important mathematical concept. Let's explore some frequent pitfalls and provide helpful tips to overcome them.

One of the most common mistakes is forgetting to distribute the term to all elements inside the parentheses. For example, in the equation 3(x + 2) = 15, some students might only multiply 3 by x, resulting in 3x + 2 = 15. The correct application of the distributive property would be 3x + 6 = 15. To avoid this error, always remember to multiply the outside term by each term inside the parentheses.

Another frequent error is mishandling negative signs when distributing. For instance, in the equation -2(x - 3) = 8, students might incorrectly write -2x - 3 = 8. The correct distribution would be -2x + 6 = 8. To prevent this mistake, pay extra attention to signs and remember that multiplying a negative by a negative results in a positive.

Students sometimes struggle with distributing fractions or decimals. In an equation like 1/2(x + 4) = 6, a common error is writing 1/2x + 4 = 6. The correct application of the distributive property is 1/2x + 2 = 6. To avoid this, practice distributing with fractions and decimals separately before incorporating them into more complex equations.

Overlooking the need for distribution entirely is another pitfall. For example, in 2x + 3(x - 1) = 10, some students might treat it as 2x + 3x - 1 = 10. The correct approach is 2x + 3x - 3 = 10. Always scan equations for parentheses and apply the distributive property where needed.

To improve your skills and avoid these common errors, consider these helpful tips:

  • Take your time and read the equation carefully before solving.
  • Write out each step of the distribution process, even if it seems simple.
  • Double-check your work, especially when dealing with negative numbers or fractions.
  • Practice with a variety of equation types to build confidence and familiarity.
  • Use visual aids, like color-coding terms or drawing arrows, to help track the distribution process.

Remember, making mistakes is a natural part of the learning process. Each error is an opportunity to deepen your understanding and improve your problem-solving skills. With practice and attention to detail, you'll become more proficient in applying the distributive property and solving equations accurately. Don't get discouraged if you make mistakes; instead, use them as stepping stones to mastery. Keep practicing, stay patient with yourself, and celebrate your progress along the way!

Practice Problems and Solutions

Welcome to our practice problems and solutions section! Here, you'll find a range of equations to solve, from simple to more complex. We encourage you to attempt these problems on your own before checking the solutions. This approach will help strengthen your problem-solving skills and deepen your understanding of mathematical concepts.

Problem 1: Basic Algebra

Solve for x: 2x + 5 = 13

Solution:

  1. Subtract 5 from both sides: 2x = 8
  2. Divide both sides by 2: x = 4

Explanation: We isolate the variable by moving the constant to the other side, then divide to solve for x.

Problem 2: Quadratic Equation

Solve: x² - 5x + 6 = 0

Solution:

  1. Identify a = 1, b = -5, c = 6
  2. Use the quadratic formula: x = [-b ± (b² - 4ac)] / 2a
  3. Plug in values: x = [5 ± (25 - 24)] / 2
  4. Simplify: x = (5 ± 1) / 2
  5. Two solutions: x = 3 or x = 2

Explanation: The quadratic formula helps us find solutions when factoring is not straightforward.

Problem 3: Systems of Equations

Solve the system:
2x + y = 7
x - y = 1

Solution:

  1. Add the equations: 3x = 8
  2. Solve for x: x = 8/3
  3. Substitute x in the second equation: 8/3 - y = 1
  4. Solve for y: y = 5/3

Explanation: By combining equations, we can eliminate one variable and solve for the other.

Problem 4: Trigonometry

Find the value of x: sin(x) = 0.5

Solution:

  1. Recall that sin(30°) = 0.5
  2. Therefore, x = 30° or 150° (in the unit circle)

Explanation: We use our knowledge of common angle values in trigonometry to solve this.

Problem 5: Calculus - Differentiation

Find the derivative of f(x) = 3x² - 2x + 1

Solution:

  1. Use the power rule for 3x²: 3 * 2x = 6x
  2. Use the power rule for -2x: -2
  3. The constant 1 becomes 0
  4. Combine terms: f'(x) = 6x - 2

Explanation: We apply differentiation rules to each term and combine the results.

Problem 6: Probability

A bag contains 3 red balls, 4 blue balls, and 5 green balls. What is the probability of drawing a red ball?

Solution:

Real-World Applications

Solving two-step linear equations with distributive property is not just a mathematical exercise confined to the classroom; it has numerous real-world applications across various fields. Understanding this concept can be incredibly beneficial in practical situations, helping individuals make informed decisions and solve complex problems efficiently.

In physics, two-step linear equations with distributive property are frequently used to solve problems related to motion and force. For example, when calculating the distance traveled by an object under constant acceleration, physicists use the equation d = vt + (1/2)at^2. This equation requires the application of distributive property and solving for different variables depending on the given information.

Economics is another field where these equations find extensive use. When analyzing supply and demand curves, economists often need to solve equations that involve multiple variables and coefficients. For instance, determining the equilibrium price and quantity in a market requires solving simultaneous linear equations, which may involve distributive property.

In everyday life, we encounter situations where two-step linear equations with distributive property can be applied. Consider planning a budget for a home renovation project. You might need to calculate the total cost of materials, factoring in different quantities and prices for various items. This could involve equations like Total Cost = 2(Paint Price) + 3(Tile Price) + Labor Cost, where you need to distribute the coefficients and solve for different variables.

Financial planning is another area where these equations prove useful. When calculating compound interest or determining loan payments, financial advisors often use formulas that require the application of distributive property and solving multi-step equations.

In the field of engineering, two-step linear equations with distributive property are essential for designing and analyzing structures. Engineers use these equations to calculate stress, strain, and load distribution in buildings and bridges, ensuring safety and stability.

Understanding this concept can be beneficial beyond the classroom by enhancing problem-solving skills and logical thinking. It helps individuals break down complex problems into manageable steps, a skill that is valuable in many professional and personal situations. Moreover, it fosters a deeper understanding of mathematical relationships, which is crucial in data analysis and decision-making processes across various industries.

By mastering two-step linear equations with distributive property, students develop a strong foundation for more advanced mathematical concepts. This knowledge serves as a stepping stone to calculus, linear algebra, and other higher-level mathematics, which are fundamental in fields like computer science, data science, and artificial intelligence.

Conclusion

In this article, we've explored the essential steps for solving two-step linear equations, emphasizing the crucial role of the distributive property in equations. We've covered how to isolate variables in equations, combine like terms, and use inverse operations in algebra to find solutions. Understanding the distributive property in equations is key to successfully tackling these equations, as it allows you to simplify expressions and make solving more manageable. Regular practice is vital to mastering two-step equations, so we encourage you to work through various problems consistently. Don't forget to revisit the introductory video for a visual refresher on the concepts discussed. By honing your ability to solve two-step linear equations, you'll build a strong foundation for more advanced mathematical concepts. We invite you to explore further resources on this topic and challenge yourself with increasingly complex equations. Remember, each problem solved brings you closer to mathematical proficiency. Keep practicing, and don't hesitate to seek additional guidance when needed!

Example:

Solve the equation using model. 4(x+1)=124\left( {x + 1} \right) = 12

Step 1: Understand the Problem

To solve the equation 4(x+1)=124(x + 1) = 12 using a model, we need to understand what the equation represents. The equation tells us that we have four groups of x+1x + 1 and that these groups together equal 12. Our goal is to find the value of xx.

Step 2: Represent the Equation Visually

We start by representing the left side of the equation visually. We have four groups of x+1x + 1. This means we need to draw four sets of xx tiles and four sets of +1 tiles. Each group looks like this: x+1x + 1.

So, we draw four groups:

  • Group 1: x+1x + 1
  • Group 2: x+1x + 1
  • Group 3: x+1x + 1
  • Group 4: x+1x + 1

On the right side of the equation, we have 12 positive units. We represent this by drawing 12 positive tiles.

Step 3: Simplify the Visual Representation

Next, we simplify the visual representation. We combine all the xx tiles and all the +1 tiles on the left side. This gives us:

  • 4 xx tiles
  • 4 +1 tiles

So, the left side of the equation is now represented as 4x+44x + 4. The right side remains as 12 positive tiles.

Step 4: Isolate the Variable

To isolate the variable xx, we need to get rid of the +4 on the left side. We do this by adding -4 (negative 4) to both sides of the equation. This step ensures that we maintain the equality of the equation.

On the left side, adding -4 cancels out the +4, leaving us with just 4x4x. On the right side, we subtract 4 from 12, which gives us 8 positive tiles.

So, the equation now looks like this: 4x=84x = 8.

Step 5: Solve for xx

Now, we need to find the value of xx. We have 4 xx tiles that equal 8 positive tiles. To find the value of one xx tile, we divide the 8 positive tiles into 4 equal groups.

Each group will have 2 positive tiles. Therefore, each xx tile is worth 2 positive tiles.

So, x=2x = 2.

Conclusion

By using a visual model, we have successfully solved the equation 4(x+1)=124(x + 1) = 12. The value of xx is 2. This method helps in understanding the distributive property and the steps involved in isolating the variable to find its value.

FAQs

Here are some frequently asked questions about solving two-step linear equations using the distributive property:

1. What is the distributive property and how does it apply to solving equations?

The distributive property states that a(b + c) = ab + ac. In equation solving, it's used to simplify expressions within parentheses. For example, in 3(x + 2) = 15, we distribute the 3 to get 3x + 6 = 15, making the equation easier to solve.

2. Why is it important to apply the distributive property before solving the equation?

Applying the distributive property first simplifies the equation, converting it into a standard two-step linear equation. This makes the subsequent steps of isolating the variable and solving much more straightforward.

3. How do you handle negative numbers when using the distributive property?

When distributing a negative number, remember to change the signs of all terms inside the parentheses. For example, -2(x - 3) becomes -2x + 6, not -2x - 6. Pay extra attention to these sign changes to avoid errors.

4. Can the distributive property be used with variables other than x?

Yes, the distributive property works with any variable. Whether it's x, y, z, or any other letter, the principle remains the same. For instance, 4(y + 1) = 4y + 4, regardless of the variable used.

5. How can I check if I've applied the distributive property correctly?

After applying the distributive property, you can check your work by expanding the original expression and comparing it to your result. For example, if you distributed 2(x + 3) to get 2x + 6, you can verify this by multiplying 2 by x and 2 by 3 separately.

Prerequisite Topics

Understanding the foundation of algebra is crucial when tackling more complex problems like solving two-step linear equations using the distributive property: a(x + b) = c. To master this concept, it's essential to grasp several prerequisite topics that build the necessary skills and knowledge.

One of the fundamental skills required is simplifying algebraic expressions. This ability allows you to manipulate and simplify the equation a(x + b) = c, making it easier to solve. Similarly, combining like terms is crucial when working with distributive property, as it helps in organizing and simplifying the equation after expansion.

When dealing with two-step equations, you'll often encounter solving equations with variables on both sides. This skill is particularly relevant as it prepares you for more complex equation structures and teaches you how to balance equations effectively.

Isolating variables in equations is another critical skill that directly applies to solving two-step linear equations. It teaches you how to manipulate the equation to get the variable by itself, which is a key step in the solving process.

Understanding the concept of applying inverse operations in algebra is vital when solving equations. This principle is used extensively in two-step equations to isolate the variable and find its value.

Another important aspect is understanding negative signs in equations. This skill is crucial when dealing with the distributive property, as it affects how terms are combined and simplified.

Lastly, proficiency in solving equations with fractions and decimals is beneficial, as these types of numbers often appear in real-world applications of two-step linear equations.

By mastering these prerequisite topics, you'll build a strong foundation for tackling more advanced concepts like solving two-step linear equations using the distributive property. Each of these skills contributes to your overall understanding and ability to approach complex algebraic problems with confidence. Remember, algebra is a cumulative subject, and each new concept builds upon previous knowledge. So, take the time to thoroughly understand these prerequisites, and you'll find yourself well-prepared for the challenges ahead in your algebraic journey.