Question

If f(x) = 1/2x – 10, then f^-1(x) =

Answer 1

f^-1 (x) = 2x+20

Explanation:

f(x) = 1/2x – 10

To find the inverse, replace f(x) with y

y = 1/2 x -10

Exchange x and y

x = 1/2 y- 10

Solve for y

Add 10 to each side

x+10 = 1/2 y-10+10

x+10 = 1/2 y

Multiply by 2

2(x+10) = 1/2y *2

2x+20 = y

The inverse is

f^-1 (x) = 2x+20