Which function has an inverse that is also a function?

g (x) = 2x - 3

k (x) = - 9x2

f (x) = |x + 2|

w (x) = - 20

The easy way to tell if it's a function is that the highest power is 1

find the inverses

the inverse is flipped over the x=y

first one

g⁻¹ (x) = 1/2x+3/2

tat's a fuction

2nd one

k⁻¹ (x) = is not a function

3rd one, this is not a function because of math, if you graph and flip, it isn't

last one, the inverse is x=-20, so that is not a fucntion

answe is first one g (x) = 2x-3