SHUXUETIMU

全数字不好看
换成未知数
设x=1.345 那么2x=2.69
则原式=x*(x-1)*2x-x^3-x*(x-1)^2
=-x*[-2x(x-1)+x^2+(x-1)^2]
=-x*[x-(x-1)]^2 (完全平方公式)
=-x*1^2
=-x
=-1.345

这次该给分了吧~!

=1.345*0.345*(2.69-0.345)-1.345*1.345*1.345
=1.345*0.345*1.345-1.345*1.345*1.345
=1.345*1.345*(0.345-1.345)
=1.345*1.345*(-1)
=-1.345的平方

具体多少就不知道了

没怎么看明白