A car dealership advertises a 20% discount on all its new cars. In addition, the manufacturer offers a $1000 rebate on the purchase of a new car. Let x represent the sticker price of the car. (a) Suppose only the 20% discount applies. Find a function f that models the purchase price of the car as a function of the sticker price x. f(x) = (b) Suppose only the $1000 rebate applies. Find a function g that models the purchase price of the car as a function of the sticker price x. g(x) = (c) Find a formula for H = fog. = H(x) = (d) Find H-1(13,500). (Round your answer to the nearest whole number.) H-1(13,500)=