Question

Which function is the inverse of f(x) =2x +3

Answer 1

f(x)=

`f(x) = 2x + 3`

`let y = 2x + 3`
make y subject of the formula

`x = (y - 3)/(2)`
replace y with x above

`f ^( - 1 ) = (x - 3)/(2)`

Answer 2

-1

f (x) = x/2 - 3/2

Explanation:

I choose to address this question by actually finding the inverse of f(x) = 2x + 3.

1) replace f(x) with y: y = 2x + 3

2) interchange x and y: x = 2y + 3

3) solve this result for y: 2y = x - 3 , or y = (x - 3)/2. This is the same as the second answer choice. Label this result as

-1

f (x) = x/2 - 3/2