Question

a+1/a^2-ab - 1-b/b^2-ab

Answer 1

$\dfrac{a+1}{a^2-ab} - \dfrac{1-b}{b^2-ab} = \dfrac{a+1}{-a(-a+b)} - \dfrac{1-b}{b(b-a)} = \\\\\\= -\dfrac{a+1}{(-a+b)}-\dfrac{1-b}{b(b-a)} = - \dfrac{b(a+1)+a(1-b)}{ab(-a+b)} = \\\\\\=-\dfrac{-ab+b+a-ab}{-a^2b+ab^2} = - \dfrac{b+a}{-a^2b+ab^2}$