Factorize the following:

The greatest common factor of the terms $72 x^{6} y^{7}$ and $-96 x^{7} y^{6}$ of the expression $72 x^{6} y^{7}-96 x^{7} y^{64}$ is $24 x^{6} y^{6}$.

Now,

$72 x^{6} y^{7}=24 x^{6} y^{6} \times 3 y$

and

$-96 x^{7} y^{6}=24 x^{6} y^{6} \times-4 x$

Hence, the expression 72x6y7 - 96x7y6 can be factorised as 24x6y6(3y - 4x)​.