The given function is,
.
Or, 
To find the inverse of a function, first step is to switch x and y. Therefore,

Next stpe is to solve the above equation for y t get the inverse f f(x). Hence, multiply each sides by y + 5 to get rid of fraction form. So,

xy + 5x = 2y - 1
xy = 2y - 1 - 5x Subtract 5x from each sides to isolate y.
xy - 2y = -5x - 1 Subtract 2y from each sides.
y(x - 2) = -5x -1 Take out the common factor y.
Divide each sides by x-2.

So, 
Now when we will compare
with
then we will get a = -5, b = -1, c = 1 and d=-2
So, 
Hope this helps you!