Find the inverse of f(x)=4-x. So f^-1(x)=

Question

Please help ASAP I'm confused!!! :(

Answer 1

swap variables and solve for the new y
y = 4-x
swap:
x = 4-y
y = 4-x
Hah! f(x) is its own inverse.
Check:
f(f^-1(x)) = 4-f^-1(x) = 4-(4-x) = x
f^-1(f(x)) = 4-f(x) = 4-(4-x) = x