Applicare la formula: $\frac{a}{\frac{b}{c}}$$=\frac{ac}{b}$, dove $a=1$, $b=-\left(x-1\right)$, $c=x^2$, $a/b/c=\frac{1}{\frac{-\left(x-1\right)}{x^2}}$ e $b/c=\frac{-\left(x-1\right)}{x^2}$

Applicare la formula: $b\cdot dy=a\cdot dx$$\to \int bdy=\int adx$, dove $a=\frac{x^2}{-\left(x-1\right)}$, $b=\frac{y^2}{y+1}$, $dyb=dxa=\frac{y^2}{y+1}dy=\frac{x^2}{-\left(x-1\right)}dx$, $dyb=\frac{y^2}{y+1}dy$ e $dxa=\frac{x^2}{-\left(x-1\right)}dx$