年级 | 科目 | 问题描述 | 提问时间 |
六年级 | 数学 | 提升训练 | 2014-06-03 17:40:20 |
(1+0.12+0.23)*(0.12+0.23+0.34)—(1+0.12+0.23+0.34)*(0.12+0.23) | |||
王老师 2014-06-03 17:54:45 | |||
遇到这种复杂的,一般都会把复杂的变的简单一些 解:设0.12+0.23=x, 0.12+0.23+0.34=y. | |||
余雯馨老师 2014-06-03 17:54:54 | |||
王老师 2014-06-03 17:55:32 | |||
(1+0.12+0.23)×(0.12+0.23+0.34)-(1+0.12+0.23+0.34)×(0.12+0.23) =(1+x)y-(1+y)x, =y+xy-x-xy, =y-x, =(0.12+0.23+0.34)-(0.12+0.23), =0.12-0.12+0.23-0.23+0.34, =0.34. |