A) 4x - 7 = 2x + 15
4x - 2x = 15 + 7
2x = 22
x = 11
Проверка:
4 * 11 - 7 = 2 * 11 + 15
44 - 7 = 22 + 15
37 = 37
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б) -24 + 3х = 9х + 18
9х - 3х = -24 - 18
6х = -42
х = -7
Проверка:
-24 + 3 *(-7) = 9 * (-7) + 18
-24 - 21 = -63 + 18
-45 = -45
Ответы: а) х = 11 б) х = -7