Question

(x+1)(x-1)-(x-1)^2+(2x+1)(x-2)其中x=-8（化简求值）

Answer 1

(x+1)(x-1)-(x-1)^2+(2x+1)(x-2)
=(x-1)(x+1-x+1)+(2x²-3x-2)
=2x-2+2x²-3x-2
=2x²-x-4
当x=-8时
原式=128+8-4
=132

Answer 2

(x+1)(x-1)-(x-1)^2+(2x+1)(x-2)
=x^2-1-x^2+2x-1+2x^2-3x-2
=2x^2-x-4
=2x(-8)^2+8-4
=128+8-4
=132

追问

不是这种死板化简，是用提取公因式的方法- -跪求过程啊。。。