Question 1179409
<pre>

{{{f(x) = (ax+b)/(cx+d)}}}

Write y for f(x)

{{{y = (ax+b)/(cx+d)}}}

Interchange x and y

{{{x = (ay+b)/(cy+d)}}}

Solve for y:

{{{x(cy+d) = ay+b}}}

{{{cxy+dx = ay+b}}}

{{{cxy-ay = b - dx}}}

{{{y(cx-a) = (b-dx)}}}

{{{y = (b-dx)/(cx-a)}}} 

Write f<sup>-1</sup>(x) for y:

f<sup>-1</sup>(x) = {{{(b-dx)/(cx-a)}}} 

Edwin</pre>