Write the inverse function for the function, ƒ(x) =1/2 x + 4.

Question

Write the inverse function for the function, ƒ(x) = 1/2x + 4. Then, find the value of ƒ -1(4). Type your answers in the box.

 

ƒ -1(x) =_ x_ _

ƒ -1(4) =_

Answer 1

f(x) = y

y = 1/2x + 4

Replace every x with y and every y with x:

x = 1/2y +4

Solve for y:

x - 4 = 1/2y

2x-8 = y

f^-1(x) = 2x-8

f^-1(4) = 2*4 -8 = 0