(32 - m) · 6 - 39 = 45
(32 - m) · 6 = 45 + 39
(32 - m) · 6 = 84
32 - m = 84 : 6
32 - m = 14
m = 32 - 14
m = 18
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Проверка: (32 - 18) · 6 - 39 = 45
14 · 6 - 39 = 45
84 - 39 = 45
45 = 45