2a-3b/b2-a2 -a+3b/a2-b2 +a+2b/a2-b2
=(-2a+3b-a+3b+a+2b)/(a^2-b^2)
=(-2a+8b)/(a^2-b^2)
=-2(a-4b)/(a^2-b^2)