Question

а) $frac{1}{a} + frac{1}{a+b}$
в) $frac{1}{m+n} - frac{1}{n}$

Answer 1

$frac{1}{a} + frac{1}{a+b}= frac{a+b}{a(a+b)} + frac{a}{a(a+b)} = frac{2a+b}{a(a+b)}\ frac{1}{m+n}- frac{1}{n} = frac{n}{n(m+n)} - frac{m+n}{n(m+n)} =- frac{m}{n(m+n)}$