$\dfrac{a+b}{ab}=\dfrac{1}{a}+\dfrac{1}{b}$ dir
$-5<a\le -1/2$ $\longrightarrow\quad \dfrac{-1}{5}>\dfrac{1}{a}\ge\dfrac{-2}{1}$
$3<b\le5$ $\longrightarrow\quad \dfrac{1}{3}>\dfrac{1}{b}\ge\dfrac{1}{5}$
Taraf tarafa toplarsak,
$\dfrac{2}{15}>\underbrace{\left(\dfrac{a+b}{ab}=\dfrac{1}{a}+\dfrac{1}{b}\right)}_{0,-1}\ge\dfrac{-9}{5}$
$2$ tanedir , en büyüğü $0$ dır.