(1+0.12+0.23)×(0.12+0.23+0.34)-(1+0.12+0.23+0.34)×(0.12+0.23)=_.
问题描述:
(1+0.12+0.23)×(0.12+0.23+0.34)-(1+0.12+0.23+0.34)×(0.12+0.23)=______.
答
设0.12+0.23=x,0.12+0.23+0.34=y.则:(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+0.23-0.2...