Question

Найдите значения выражения (2 1/4 - 1 1/4*(2/7+3 1/7*1/3) ) : 0,7=

Answer 1

Выражением:
$(2 \frac{1}{4} - 1 \frac{1}{4} * ( \frac{2}{7} +3 \frac{1}{7} * \frac{1}{3} )) :0,7= \\ \\ = (2\frac{1}{4} - \frac{5}{4} *( \frac{2*3}{7*3} + \frac{22*1}{7*3} )) :0,7= \\ \\ =( 2 \frac{1}{4} - \frac{5*28}{4*21} ):0,7= \\ \\ =( \frac{9}{4} - \frac{5*1}{1*3} ) :0,7= \\ \\ = \frac{9*3- 5*4}{4*3} : 0,7= \\ \\ = \frac{7}{12} * \frac{10}{7} = \\ \\ = \frac{1*5}{6*1} = \frac{5}{6}$
По действиям:
$(2 \frac{1}{4} - 1 \frac{1}{4} * ( \frac{2}{7} +3 \frac{1}{7} * \frac{1}{3} )) :0,7=\frac{5}{6}\\ \\ 1) 3 \frac{1}{7} * \frac{1}{3}= \frac{22*1}{7*3} = 1\frac{1}{21} \\ \\ 2) \frac{2}{7} +1 \frac{1}{21} = \frac{6+22}{21} = \frac{28}{21} = \frac{4}{3} =1 \frac{1}{3} \\ \\ 3) 1 \frac{1}{4} *1 \frac{1}{3} = \frac{5*4}{4*3} = \frac{5}{3} = 1 \frac{2}{3} \\ \\ 4) 2 \frac{1}{4} - 1 \frac{2}{3} = \frac{27- 20}{12}= \frac{7}{12} \\ \\ 5) \frac{7}{12} : \frac{7}{10} = \frac{7*10}{12*7} = \frac{5}{6}$

Answer 2

( 2 1/4 - 1 1/4 х ( 2/7 + 3 1/7 х 1/3)) : 0,7=5/6. 1) 3 1/7 х 1/3 = 22/7 х 1/3 = 22/21. 2) 2/7 + 22/21 = 6/21 + 22/21 = 28/21, 3) 1 1/4 х 28/21 = 5/4 х 28/21 = 35/21; 4) 2 1/4 - 35/21 = 9/4 - 35/21 = 189/84 - 140/84 = 49/84. 5) 49/84 : 0,7 = 49/84 : 7/10 = 49/84 х 10/7 = 70/84 = 10/12= 5/6.