1) 8(x-14) = 56
8x - 112 = 56
8x = 56 + 112
8x = 168
x = 168/8
x = 21

Ответ: x = 21

3) 9(143-13x) = 234
1287 - 117x = 234
-117x = 234 - 1287
-117x = -1053
x = -1053 / -117
x = 9

Ответ: x = 9