Question

Let f(x)=2x+2 solve f^-1(x)when x=4

Answer 1

basically to find f^(-1)(x) you could actually find that formula for f^(-1)(x)

or since f^(-1)(4)=y implies f(y)=4 you could just solve f(y)=4 for y to get your answer
so f(y)=2y+2
f(y)=4
replace f(y) with 2y+2 so we have
2y+2=4

Answer 2

solve