(1/2-1/3+3/4-4/5)X(-60)=-7
{1/3-(-1/9+7/12)}X(-36)=5
(-61)X36-27X36+12X(-36)=-3600
3 1/2X(-5/7)-(-5/7)X2 1/2-5/7X(-1/2)=45/14
乘法分配律吧(不太确定)
(1/2-1/3+3/4-4/5)X(-60)=-7
{1/3-(-1/9+7/12)}X(-36)=5
(-61)X36-27X36+12X(-36)=-3600
3 1/2X(-5/7)-(-5/7)X2 1/2-5/7X(-1/2)=45/14
乘法分配律吧(不太确定)