56 - 2х = 36
56 - 36 = 2х
2х = 56 - 36
2х = 20
х = 20 : 2
х = 10
Проверка:
56 - 2 * 10 = 36
56 - 20 = 36
36=36
Ответ: х = 10
34 - 2 * (2х - 9) = 28
34 - 28 = 2 * (2х - 9)
2 * (2х - 9) = 34 - 28
2 * (2х - 9) = 6
2х - 9 = 6 : 2
2х - 9 = 3
2х = 3 + 9
2х = 12
х = 12 : 2
х = 6
Проверка:
34 - 2 * (2 * 6 - 9) = 28
34 - 2 * (12 - 9) = 28
34 - 2 * 3 = 28
34 - 6 = 28
28 = 28
Ответ: х = 6