Do the grouping $x^{2}y-x^{3}-y+x=\left(x^{2}y-x^{3}\right)+\left(-y+x\right)$, and factor out $x^{2}$ in the first and $-1$ in the second group.
$$x^{2}\left(-x+y\right)-\left(-x+y\right)$$
Factor out common term $-x+y$ by using distributive property.
$$\left(-x+y\right)\left(x^{2}-1\right)$$
Consider $x^{2}-1$. Rewrite $x^{2}-1$ as $x^{2}-1^{2}$. The difference of squares can be factored using the rule: $a^{2}-b^{2}=\left(a-b\right)\left(a+b\right)$.
