UC知道高中数学 因式分解
来源：百度知道 编辑：UC知道 时间：2024/05/29 10:33:08
x^3-11x^2+31x-21
在线等答案 速求
在线等答案 速求
x^3-11x^2+31x-21
=x^3-x^2-[10x^2-31x+21]
=x^2[x-1]-[10x-21][x-1]
=[x-1][x^2-10x+21]
=[x-1][x-3][x-7]
x^3-11x^2+31x-21
=x^3-x^2-[10x^2-31x+21]
=x^2[x-1]-[10x-21][x-1]
=[x-1][x^2-10x+21]
=[x-1][x-3][x-7]
x^3-11x^2+31x-21
=x^3-x^2-[10x^2-31x+21]
=x^2[x-1]-[10x-21][x-1]
=[x-1][x^2-10x+21]
=[x-1][x-3][x-7]
x^3-11x^2+31x-21 =x^3-x^2-10x^2+10x+21x-21=x^2(x-1)-10x(x-1)+21(x-1)=
(x^2-10x+21)(x-1)=(x-3)(x-7)(x-1)
原式=（X-1）×（X-3）×（X-7）
用交叉相乘法，你自己可以试试^_^
(x-1)(x-3)(x-7)