Question

x的三次方加X的二次方加X减1等于零怎么解,加思路,

Answer 1

x^3+x^2+x-1=0
(x^3-x)+（x^2-1)=0
x(X^2-1)+(x-1)(x+1)=0
x(x-1)(x+1)+(x-1)(x+1)=0
(x+1)(x-1)(x+1)=0
每一项=0
解得x=1或-1