Question

Выполните умножение   b/a-b*(1/a-1/b)

Answer 1

$\displaystyle \frac{b}{a-b}* (\frac{1}{a}- \frac{1}{b})= \frac{b}{a-b}*( \frac{b-a}{ab})= \frac{b(b-a)}{(a-b)*ab}= \frac{-b(a-b)}{(a-b)*ab}=- \frac{1}{a}$