How do you factor a^2(x-y) + 5(y-x)?

Jun 5, 2016

$\left(x - y\right) \left({a}^{2} - 5\right)$

Explanation:

let's change sign two times:

${a}^{2} \left(x - y\right) - 5 \left(x - y\right)$

so we can find the common factor (x-y):

$\left(x - y\right) \left({a}^{2} - 5\right)$