Ответ:

Пошаговое объяснение:

1) 1 13/15 * 1 19/21 = 28/15 * 40/21 = 32/9 = 3 5/9

2) 6 - 3 5/9 = 2 4/9

3) 81/88 * 2 4/9 = 81/88 * 22/9 = 9/4 = 2 1/4

ответ: 2 1/4

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-2 + (2+x)/7 = -5x/2     ||*14

-28 + 4 + 2x = -35x

-24 + 2x = -35x

2x + 35x = 24

37x = 24

x = 24 : 37

x = 24/37