A(b-c)-(c-b) A(2+b)-(c-b) 5x-5y-ax+ay
A(b-c)-(c-b)=ab-ac-c+b a(2+b)-(c-b)=2a+ab-c+b 5x-5y-ax+ay=5(x-y)-a(x-y)=(x-y)(5-a)