Question 1071689
{{{(2ab-7a-4)-(7ab-4)=(2ab-7ab)-7a-4-(-4)}}}
{{{(2ab-7a-4)-(7ab-4)=-5ab-7a-4+4}}}
{{{(2ab-7a-4)-(7ab-4)=-5ab-7a}}}
{{{(2ab-7a-4)-(7ab-4)=-a(5b+7)}}}