For which function is f(x) not equal to f-1(x)? (need this to graduate) a. f(x)=2-x b. f(x)=2/x c. f(x)=-x d f(x)=2x

The answer would be: D. f(x)=2x
The f-1(x) is also called as an inverse function. To find the inverse function, you just need to switch the y variable with the x variable. The inverse function of f(x)=2x would be
y=2x
x'=2y'
y'= 1/2 x'

The inverse function is different with f(x)