inverse functions

Question

Let 

Answer 1

I will assume this is y=1/(x+4).

Swap your x and y

x=1/(y+4)

Multiplt both sides by y+4

x(y+4)=1

Distribute your x

xy+4x=1

Move your 4x to the right side

xy=1-4x

Divide both sides by x

y=(1-4x)/x