Question

For the function f(x)= (8-2x)^2, find f^-1. Determine whether f^-1 is a function.

Answer 1

No its not a function :) 

to find the inverse function first expand those brackets 

you'll get 
f(x)= x^2 - 2x^2 - 2x^2 = 4x^2 
f(x)= x^2 - 4x^2 + 4x^2 
f(x)= x^2 or y=x^2 


to find the inverse, swap x and y around. then make y the subject again 

y=x^2 
x=y^2 
Root of x=y 

now put -1 into x 

it wont work because roots cannot have negative numbers 
answer is no

Answer 2

f­-1(x) = 8±√x/2; f­-1 is not a function, is the answer