Question 290613
{{{3a^2/(a-b)}}} - {{{(3b^2-6ab)/(b-a)}}}
Factor out -1 to make the denominators the same
{{{3a^2/(a-b)}}} - {{{((3b^2-6ab))/(-1(a-b))}}}
the minus one changes the sign
{{{3a^2/(a-b)}}} + {{{((3b^2-6ab))/((a-b))}}}
Factor out 3
{{{(3a^2+3b^2-6ab)/(a-b)}}} = {{{(3(a^2+b^2-2ab))/(a-b)}}}
Can be written
{{{(3(a^2-2ab+b^2))/(a-b)}}}
Factor and cancel
{{{(3(a-b)(a-b))/(a-b)}}} = 3(a-b)