Question

Вычислите значение выражения (8-6 1/4): (-5/8)-9*(-1/2-2/5) 30

Answer 1

$\bigg(8-6\dfrac{1}{4}\bigg)\div\bigg(-\dfrac{5}{8}\bigg)-9\cdot\bigg(-\dfrac{1}{2}-\dfrac{2}{5}\bigg)=\bold{5,3}$

$1) \: \: 8-6\dfrac{1}{4}=7\dfrac{4}{4}-6\dfrac{1}{4}=1\dfrac{3}{4}$

$2) \: \: -\dfrac{1}{2}-\dfrac{2}{5}=-\dfrac{5}{10}-\dfrac{4}{10}=-\dfrac{9}{10}$

$3) \: \: 1\dfrac{3}{4}\div\bigg(-\dfrac{5}{8}\bigg)=\dfrac{7}{4}\cdot\bigg(-\dfrac{8}{5}\bigg)=-\dfrac{7\cdot2}{5}=-\dfrac{14}{5}$

$4) \: \: 9\cdot\bigg(-\dfrac{9}{10}\bigg)=-\dfrac{9\cdot9}{10}=-\dfrac{81}{10}$

$5) \: \: -\dfrac{14}{5}-\bigg(-\dfrac{81}{10}\bigg)=-\dfrac{28}{10}+\dfrac{81}{10}=\dfrac{81}{10}-\dfrac{28}{10}=\dfrac{53}{10}=5,3$