Вычислите: 1) (-3/14 -8/21) : 20/21 2) 3/8 : (-5/8)-(-2 1/4):(-1 4/11) 3) (-4 1/12+ 3...

Решите задачу:

$(- \frac{3}{14} - \frac{8}{21} ) : \frac{20}{21} = - (\frac{3*3 + 8*2}{42} ) * \frac{21}{20} = - \frac{25}{42} * \frac{21}{20} = - \frac{5 *1 }{2*4} = - \frac{5}{8}$

$\frac{3}{8} : (- \frac{5}{8}) -(- 2 \frac{1}{4}) : (-1 \frac{4}{11} ) = -\frac{3*8}{8*5} + \frac{9 }{4} * ( - \frac{4}{15} ) = - \frac{3}{5} - \frac{3}{5} = -\frac{6}{5} = -1 \frac{1}{5}$

$( - 4 \frac{1}{12} +3 \frac{9}{10} ) : 3 \frac{3}{10} =-( 4\frac{5}{60} - 3 \frac{54}{60}) * \frac{10}{33} =- \frac{11}{60} * \frac{10}{33} = - \frac{1*1}{6*3} = - \frac{1}{18}$

$( \frac{11}{14} - \frac{5}{6} ): ( \frac{11}{14} - \frac{3}{4} )= ( \frac{66-70}{84} ): ( \frac{44-42}{56}) = - \frac{4}{84} * \frac{56}{2} = \\ \\ = - \frac{1*28}{21*1} = - \frac{4}{3} =- 1 \frac{1}{3}$