Question

If f(x) =2x/X-5

Find f^-1(x).​

Answer 1

Explanation:

Let f(x)=y

y=2x/X-5

y(x-5)=2x

xy-5y=2x

x(y-2)=5y

x=5y/y-2

Apply x=5y/y-2, on f(x)

f(5y/y-2)=2(5y/y-2)/[(5y/y-2)-5]

=(10y/y-2)/[(5y-5y+10)/y-2]

=10y/10

=y

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