All computers are on sale for 10% off the original price. If x is the original price of the computer, then the function that rep
resents the price after only a 10% discount is: P(x) = x - 0.1x P(x) = 0.9x The function that gives the price, C, if only a $150 coupon is used is: C(x) = x - 150 Choose the composition function that gives the final sale price after a 10% discount is followed by a $150 coupon. C(P(x)) = 0.9x – 150 P(C(x)) = 0.9x – 150 C(P(x)) = 1.9x – 150 P(C(x)) = 1.9x – 150
so, if you go to the store, the item is discounted by 10%, so you're really only getting out of your pocket 90% of that, or 0.9x, but!!! wait a minute!! you have a $150 coupon, and you can use that for the purchase, so you're really only getting out of your pocket 0.9x - 150, namely the discounted by 10% and then the saving from the coupon.
As you can see only one variable is square in this situation, so it can only be a parabola. We can prove that it is a parabola however by converting it into standard form (x - h)^2 + (y - k)^2.
