2a-3b/b2-a2 -a+3b/a2-b2 +a+2b/a2-b2
=(3b-2a-a-3b+a+2b)/(a²-b²)
=(-2a+2b)/(a²-b²)
=-2(a-b)/[(a-b)(a+b)]
=-2/(a+b)