Question

$frac{a}{a+b} - frac{b}{a-b}$

Answer 1

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