71/2m+2 2/3m+1/6m=1 3/4×(-2 1/3)+4 1/5×2 5/6

- 7 1/2m + 2 2/3m + 1/6m = 1 3/4 *(- 2 1/3) +4 1/5 * 2 5/6
- 15/2m + 8/3m + 1/6m = 7/4 *(- 7/4) + 21/5 * 17/6
- 45/6m + 16/6m + 1/6m = -49/16 + 119/10
- 28/6 m = - 245/80 + 952/80
-14/3m = - 707/80
m = (707*3) / (80*14)
m = 2121/1120 = 1 1001/1120 = 1 143/160