Example 7.2.8

Factor \(xy^2-10y^2-2x+20\text{.}\) The technique can work when there are multiple variables too.

\begin{align*} xy^2-10y^2-2x+20\amp=\left(xy^2-10y^2\right)+(-2x+20)\\ \amp=\highlight{y^2}(x-10)+\highlight{(-2)}(x-10)\\ \amp=\highlight{y^2}\attention{\overbrace{(x-10)}}\highlight{-2}\attention{\overbrace{(x-10)}}\\ \amp=(x-10)\highlight{\left(y^2-2\right)}\text{.} \end{align*}
in-context