x/28 - (2X-14)/28 +(2X-14)/35 - x/35 = -1/5 通分
[5x-5*(2x-14)+4*(2x-14)-4x] /140 = -1/5
[x - (2x-14)]/140 = -1/5
-x+14 = -28
x = -42
x/28 - (2X-14)/28 +(2X-14)/35 - x/35 = -1/5 通分
[5x-5*(2x-14)+4*(2x-14)-4x] /140 = -1/5
[x - (2x-14)]/140 = -1/5
-x+14 = -28
x = -42