Решите уровнение : x+(x+10)-12+10=30

х + ( х + 10 ) - 12 + 10 = 30

2х + 10 - 12 + 10 = 30

2х + 8 = 30

2х = 30 - 8

2х = 22

х = 22 : 2

х = 11

11 + ( 11 + 10 ) - 12 + 10 = 30

11 + 21 - 12 + 10 = 30

32 - 12 + 10 = 30

20 + 10 = 30

30 = 30