2 * (30х + 15) + 3 * (14 - 15х) = 117
60х + 30 + 42 - 45х = 117
60х - 45х = 117 - 30 - 42
15х = 45
х = 45 : 15
х = 3
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2 * (30 * 3 + 15) + 3 * (14 - 15 * 3) = 117
2 * (90 + 15) + 3 * (14 - 45) = 117
2 * 105 + 3 * (- 31) = 117
210 + (- 93) = 117
210 - 93 = 117
117 = 117