Let f(x) = 9x and g(x) = x - 5. What's
the smallest number that is in the domain of
fog?

if im not mistaking its

step-by-step explanation:  

answer: hence, function will be

explanation:

since we have given that

cost of a new textbook = $85

according to question, the resale value of a textbook decreases by 25% with each previous owner,

so, our function becomes,

here, y is the total value of the text book after x owners.

hence, function will be