Need Inverse of Function Help!!!!!

Question

Let f(x)=2x+5/10x+1. Find f−1(x).

Answer 1

Let y = f(x):  y = (2x+5)/(10x+1)

 

Switch x and y:  x = (2y+5)/(10y+1)

 

Solve for y:  x(10y+1) = 2y+5

 

                  10xy + x = 2y + 5

 

                  10xy - 2y = 5 - x

 

                     y(10x - 2) = 5 - x

 

                                y = (5 - x) / (10x - 2) = f^-1(x)