x4-2x3-6x2+6x+9=0求x的值,x的4次方-2x的3...
问题描述：
x4-2x3-6x2+6x+9=0求x的值,x的4次方-2x的3...
答
x^4-2x^3-6x^2+6x+9=0
x^4-2x^3-3x^2-3x^2+6x+9=0
x^2(x^2-2x-3)-3(x^2-2x-3)=0
(x^2-2x-3)(x^2-3)=0
(x-3)(x+1)(x+√3)(x-√3)=0
x1=3
x2=-1
x3=-根号3
x4=根号3