1) 5/6 * a - 4/5 * a
+ 1 = 1/2 * a - 2/5

5/6a - 4/5a + 1 = 1/2a - 2/5

5/6a - 4/5a - 1/2a = - 1 - 2/5

25/30a - 24/30a - 15/30a = -1 2/5

-14/30a = -1 2/5

a = -1 2/5 : -14/30

a = 3

ответ: a = 3

Пошаговое объяснение:

5/6а - 4/5а + 1 = 1/2а - 2/5

25/30а - 24/30а + 1 = 15/30а - 2/5

1/30а + 1 = 15/30а - 2/5

1/30а - 15/30а = -2/5 - 1

-14/30а = -1. 2/5

-7/15а = -7/5

а = -7/5 : (-7/15)

а = -7/5 * (-15/7)

а = -1/1 * (-3/1)

а = 3/1

а = 3