Question

If f(x) = 5x – 3, then what is f^-1(x) ?
a.(x+5)/3
b.(x-5)/3
c.(x+3)/5
d.(x-3)/5

Answer 1

Let f(x) by y. y = 5x - 3 so f^-1 (x) = x = 5y - 3 (Note that x and y have been replaced to each other)

Now isolate y to find the inverse function.

Answer 2

I'm still confused my teacher did not explain anything at all

Answer 3

This site explains everything: http://www.mathsisfun.com/sets/function-inverse.html