Question: Find the value
$x^{2}+y-x y-x$
Solution:
On rearranging
$x^{2}-x y-x+y$
Taking $x$ common in the $\left(x^{2}-x y\right)$ and $-1$ in $(-x+y)$
$=x(x-y)-1(x-y)$
Taking $(x-y)$ common in the terms
$=(x-y)(x-1)$
$\therefore x^{2}+y-x y-x=(x-y)(x-1)$
