Question

Вычислите а) 5/6+(-7/12) б) -3/10-1/15 в)-3/5*5/9 г) 8/21: (-4/7)

Answer 1

Пошаговое объяснение:

а)

$\tt\displaystyle \frac{5}{6}+ (-\frac{7}{12} )=\frac{5*2}{6*2} -\frac{7}{12}=\frac{10}{12}-\frac{7}{12}=\frac{10-7}{12}=\frac{3}{12}=\frac{3:3}{12:3}=\frac{1}{4}=0,25$

б)

$\tt\displaystyle -\frac{3}{10}-\frac{1}{15}=-\frac{3*3}{10*3}-\frac{1*2}{15*2}=-\frac{9}{30}-\frac{2}{30}=\frac{-9-2}{30}=-\frac{11}{30}$

в)

$\tt\displaystyle -\frac{3}{5}*\frac{5}{9}=-\frac{3*5}{5*3*3} =-\frac{1}{3}$

г)

$\tt\displaystyle \frac{8}{21} :(-\frac{4}{7} )=\frac{8}{21}*(-\frac{7}{4} )=-\frac{2*4*7}{3*7*4}=-\frac{2}{3}$