Question

A^3b-ab^3/a^2+ab-3a-3b

Answer 1

$frac{a^3b-ab^3}{a^2+ab-3a-3b} = frac{ab(a^2-b^2)}{a(a+b) - 3(a+b)} = \ \ = frac{ab(a-b)(a+b)}{(a-3)(a+b)} = frac{ab(a-b)}{a-3}$

Answer 2

a^3b-ab^3/(a^2+ab-3a-3b)=ab(a^2-b^2)/(a(a+b)-3(a+b))=

ab(a-b)(a+b)/(a+b)(a-3)=ab(a-b)/(a-3).