【初一下】【回答后给分】已知x²-2x=2,将代数式(x-1)²+(x+3)(x-3)+(x-3)(x-1)化简并求值.
问题描述:
【初一下】【回答后给分】已知x²-2x=2,将代数式(x-1)²+(x+3)(x-3)+(x-3)(x-1)化简并求值.
答
(x-1)²+(x+3)(x-3)+(x-3)(x-1)=(x-1)²+(x-3)[(x+3)+(x-1)]=(x-1)²+(x-3)[2x+2]=x²-2x+1+2x²+2x-6x-6=2+1+2x²-4x-6=3+2(x²-2)-6=3+4-6=1