Question

If f(x) = x minus 3, all over 3, then what is f-1(x) ?

one-thirdx - 1
3x - 1
3x - 3
3x + 3
which one?

Answer 1

To find inverses, first replace f(x) with y for ease of notation: y = (x-3)/3
Second change every x to a y and every y to an x: x = (y-3)/3
Third, solve for y:
x = (y-3)/3
3x = y - 3
3x + 3 = y
So, the inverse is: 3x + 3