小明邮票张数的3/4和小华的4/5相等,小明的邮票张数是小华的()(1+1/2+1/3+1/4)×(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)×(1/2+1/3+1/4)4x-1/6=8/3 解方程

问题描述:

小明邮票张数的3/4和小华的4/5相等,小明的邮票张数是小华的()
(1+1/2+1/3+1/4)×(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)×(1/2+1/3+1/4)
4x-1/6=8/3 解方程

小明邮票张数的3/4和小华的4/5相等,小明的邮票张数是小华的十六分之十五(15/16)
3/4=4/5
通分后就可看清楚
15/20=16/20
即15/16
(1+1/2+1/3+1/4)×(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)×(1/2+1/3+1/4)
=1×(1/2+1/3+1/4+1/5)+(1/2+1/3+1/4)×(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)×(1/2+1/3+1/4)
=(1/2+1/3+1/4+1/5)+(1/2+1/3+1/4)×[(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)]
=(1/2+1/3+1/4+1/5)+(1/2+1/3+1/4)×[-1]
=(1/2+1/3+1/4+1/5)-(1/2+1/3+1/4)
=1/5
4x-1/6=8/3
4x=1/6+8/3
4x=17/6
x=17/24