1/3(5/12-4m)=4/9(1 1/2m-3/8)

1/3(5/12-4m)=4/9(1 1/2m-3/8)1/3*5/12-1/3*4m=4/9*3/2m-4/9*3/85/4-4/3m=2/3m-1/65/4+1/6=2/3m+4/3m15/12+2/12=6/3m17/12=6/3mm=17/12:6/3m=17/24