# How do you factor by grouping  x^2-x-x+1 ?

${\left(x - 1\right)}^{2}$
$x \left(x - 1\right) - 1 \left(x - 1\right) = \left(x - 1\right) \left(x - 1\right) = {\left(x - 1\right)}^{2}$