(lgx)2+lgx^3+2=0解方程(logx)^2+lgx^3+2=0
问题描述：
(lgx)2+lgx^3+2=0解方程
(logx)^2+lgx^3+2=0
答
(lgx)^2+lgx^3+2=0
(lgx)^2+3lgx+2=0
(lgx+1)(lgx+2)=0
lgx = -1，或lgx = -2
x = 10^(-1) = 0.1，或x = 10^(-2) = 0.01
答
(lgx)2+lgx^3+2=0
(lgx)2+3lgx+2=0
令lgx=t，则
t²+3t+2=0
（t+1）（t+2）=0
所以t=-1或t=-2
即lgx=-1，所以x=0.1，
或lgx=-2，x=0.01
答
(lgx)^2+lgx^3+2=0
(lgx)2+3lgx+2=0
(lgx+2)(lgx+1)=0
lgx=-2或lgx=-1
x=1/100或x=1/10