3:6х +7= 3:5х-7
3/6х-3/5х = -7-7
15/30х-18/30х = -14
-3/30х = -14
-1/10х=-14
10х = 1/14
х =1/14:10
х = 1/14*1/10
х = 1/140
3:6*1/140+7 = 3:5*1/140 -7
3: 6/140+7 = 3:5/140-7
3*140/6+7 = 3*140/5 -7
140/2 +7 = 420/5-7
70+7 = 84-7 = 77
ответ: 1/140.
/ - дробь
3/6x + 7 = 3/5x -7 | всё умноажем на 30x
15 + 210x = 18 - 210x
420x = 3
x = 3/420 = 1/140
ответ: x = 1/140
