15.4 Solving quadratic equations by completing the square

Solving quadratic equations by completing the square

When a quadratic equation cannot be factorized, we can use the method of completing the square to solve the equation.

Lessons

Notes:
4-step approach:
1. isolate X’s on one side of the equation
2. factor out the leading coefficient of X2X^2
3. “completing the square”
• X-side: inside the bracket, add (half of the coefficient of X)2X)^2
• Y-side: add [ leading coefficient \cdot (half of the coefficient of X)2X)^2 ]
4. clean up
• X-side: convert to perfect-square form
• Y-side: clean up the algebra
Teacher pug

Solving quadratic equations by completing the square

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