Question 145442
f(x)=x/x-1 
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y = x / (x-1)

Interchange x and y to get:
x = y/(y-1)
Solve for y:

y = xy - x
xy -y = x
y(1-x) = x 
y = x/(1-x) is the inverse of y = x(x-1)
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Cheers,
Stan H.