-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

-4 1/6m = -4 9/12 + 9 5/6

-4 1/6m = 5 3/4

m = -1 3/4