20*（1-m%）*(5-7.5m%+1.5)=24
==>20*(1-m%)(6.5-7.5m%)=24
==>(1-m%)(65-75m%)=12
==>5*(1-m%)(13-15m%)=12.
有未知数的等式化简20*（1-m%）*(5-7.5m%+1.5)=24化简.就是这样.
20*（1-m%）*(5-7.5m%+1.5)=24
==>20*(1-m%)(6.5-7.5m%)=24
==>(1-m%)(65-75m%)=12
==>5*(1-m%)(13-15m%)=12.