-7 1/2m+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

-3 1/6m = -4 11/12 + 8 1/5

-3 1/6m = 3 1/60

m = -4/3