Question

алгебра, упростить выражение.

Answer 1

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