t^3-3t+2=0,t=?
问题描述：
t^3-3t+2=0,t=?
答案是1和-2，求思路
答
t^3-3t+2=0
t^3-1-3t+3=0
(t^3-1)-(3t-3)=0
(t^3-1)-3(t-1)=0
(t-1)*(t^2+t+1-3)=0
(t-1)*(t^2+t-2)=0
t-1=0
t=1
t^2+t-2=0
(t+2)(t-1)=0
t+2=0
t=-2
t-1=0
t=1