cvetlana , ответ добавлен 05.08.2018 в 16:18

. . (1/6 + 1/7) * (1/13 - 1/2)= - 11/21

1) 1/6+1/7=7/42+6/42=13/42

2) 1/13 - 1/2=2/26 - 13/26= - 11/26

3) 13/42 * ( -11/26)= - 22/42= - 11/21

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. - 19 1/2 : (-4 2/3 - 78,52 : 5,2)=585/593

1) 78,52 : 5,2=15,1

2) -4 2/3 - 15,1= - 4 2/3 - 15 1/10= - 4 20/30 - 15 3/30= - 19 23/30

3) - 19 1/2 : (-19 23/30)=39/2 * 30/593=585/593

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