1 原式=（-7/12)x(-24)+(5/6)x(-24)-1x(-24)=14-20+24=-6+24=18

2 原式=42x(-2/3)-(-3/4)÷（-1/4)=42x(-2/3)-(-3/4)x4=(-84/3)-3=(-9/3)-(84/3)=-31