Applications of linear equations

Lessons

1. Find the equation of a line parallel to 3x + 5y = 9 with the same y-int as 4x -5y = 12
2. Find the equation of a line perpendicular to 3x + 4y = 12 with the same x-int as 2x - 6y = 0
3. Lines A & B are perpendicular and have the same x-int. The equation of line A is x + 2y - 4 = 0. Determine the y-int of line B.
4. Alex bought 144 bagels for $80. His profit was $75 once he had sold 100 bagels. Find the equation that represents Alex's profit P as a function of the number sold, n?
5. A super computer still has the value of $80,000 after two years, and $50,000 after four years. Determine the purchase price of the super computers
6. A house was purchased for $500,000. The owner expects the house to double in value in the next 12 years. Find the appreciation equation.
7. The total cost of a car is the sum of the selling price, plus a sales tax of 5%, plus a $100 environmental fee.
   i)
   Express the total cost of the car as a linear function of the selling price.
   ii)
   What is the total cost of a car that sells for $56,000?
   iii)
   What is the selling price of a car whose total cost was $72,000?