Question

Given f(x)=4-x^2 for x is less than or equal to 0, find f^-1(x).

Answer 1

first replace
f(x) with y
y=4-x^2
now replace each x with y and each y with x
x=4-y^2
now solve for y

Answer 2

so y = sqrt(4-x) ?

Answer 3

yes replace y with f^-1(x) !!

Answer 4

Ok thank you!