-3Х + 10Х = 15 - 6
7Х = 9
Х = 9 : 7 ( ДРОБЬ )
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7Х - 5Х = 17 - 35
2Х = - 18
Х = - 18 : 2
Х = -9
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5Х - 7Х = -35 + 37
2Х = 2
Х = 2 : 2
Х = 1
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-2Х -11Х = -45 + 6
-13Х = - 39
Х = -39 : ( -13)
Х = 3