$$b { m }^{ 2 } +b { y }^{ 2 } -c { m }^{ 2 } -c { y }^{ 2 }$$
Factor
$\left(b-c\right)\left(y^{2}+m^{2}\right)$
Solution Steps
Do the grouping $bm^{2}+by^{2}-cm^{2}-cy^{2}=\left(bm^{2}+by^{2}\right)+\left(-cm^{2}-cy^{2}\right)$, and factor out $b$ in the first and $-c$ in the second group.
