Composición de funciones

Dadas $f (x) = x - 1$ y $g (x) =\dfrac{x^2}{1-x}$, calculad $(f \circ g) (x)$.

$$(f \circ g) (x)=f(g(x))=g(x)-1=\dfrac{x^2}{1-x}-1=\dfrac{x^2-1+x}{1-x}=\dfrac{x^2+x-1}{1-x}$$

$(f \circ g) (x)=\dfrac{x^2+x-1}{1-x}$