(7x+24):13+71=74 чему = x
Решение:
(7x + 24) : 13 + 71 = 74
(7x + 24) : 13 = 74 - 71
(7x + 24) : 13 = 3
7x + 24 = 3 * 13
7x + 24 = 39
7x = 39 - 24
7x = 15
x = 15 : 7