化简,求值:(x+1)²-(x+1)(x-1)+3(1-x)²,x=负二分之一
问题描述:
化简,求值:(x+1)²-(x+1)(x-1)+3(1-x)²,x=负二分之一
急!
答
代数式可化为x^2+2x+1-x^2+1+3x^2-6x+3=3x^2-4x+5,将x=-1/2代入上式,得31/4
化简,求值:(x+1)²-(x+1)(x-1)+3(1-x)²,x=负二分之一
急!
代数式可化为x^2+2x+1-x^2+1+3x^2-6x+3=3x^2-4x+5,将x=-1/2代入上式,得31/4