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| Question 983509:  Hello, I really need some help on this problem I was assigned. It's pretty challenging.. Thank you in advance!
 You have a $50 coupon from the
 manufacturer good for the purchase of a cell phone. The store
 where you are purchasing your cell phone is offering a 20%
 discount on all cell phones. Let x represent the regular price of
 the cell phone.
 (a) Suppose only the 20% discount applies. Find a function f
 that models the purchase price of the cell phone as a function of the regular price x
 (b) Suppose only the $50 coupon applies. Find a function g
 that models the purchase price of the cell phone as a function
 of the sticker price x.
 (c) If you can use the coupon and the discount, then the purchase
 price is either (f o g)x or (g o f)x , depending on the
 order in which they are applied to the price. Find both (f o g)x and (g o f)x . Which composition gives the lower price?
 Answer by macston(5194)
      (Show Source): 
You can put this solution on YOUR website! Let x = regular price of the cell phone. (a) Suppose only the 20% discount applies.
 .
 f(x)=0.8x
 .
 (b) Suppose only the $50 coupon applies.
 .
 g(x)=x-$50
 .
 (c) If you can use the coupon and the discount, then the purchase
 price is either (f o g)x or (g o f)x.  Which composition gives the lower price?
 .
 f(g(x))=0.8(x-$50)
 g(f(x))=0.8x-$50 This is the lower price.
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