Question 1071246
{{{-5(x-3y)^2 + 7(3y-x)=-5(x-3y)^2 -7(x-3y)}}}
That makes you see a {{{(x-3y)}}} common factor, so
{{{-5(x-3y)^2 + 7(3y-x)=(x-3y)(-5(x-3y)-7)}}}
{{{-5(x-3y)^2 + 7(3y-x)=highlight((x-3y)(-5x+15y-7))}}}
There are other equivalent alternative factored forms,
because you can play with the order of terms and the minus signs,
as in the examples below.
{{{-5(x-3y)^2 + 7(3y-x)=highlight((x-3y)(3y-15x-7))}}}
{{{-5(x-3y)^2 + 7(3y-x)=highlight(-(x-3y)(15x-3y+7))}}}
{{{-5(x-3y)^2 + 7(3y-x)=highlight((3y-x)(15x-3y+7))}}}