题目

(1)log(a)x=2,log(b)x=1,log(c)x=4求log(abc)x
(2)如果方程lg^2x+(lg2+lg3)lgx+lg2*lg3=0的两个根为x1,X2,求X1*x2

提问时间：2020-10-27

答案

1.log(a)x=2,log(b)x=1,log(c)x=4 => x=a^2=b=c^4 => a=c^2
log(abc)x=log(c^7)c^4=4/7
2.lg^2x+(lg2+lg3)lgx+lg2*lg3=0
(lgx+lg2)(lgx+lg3)=0
lgx=-lg2或lgx=-lg3
x1=1/2 x2=1/3
x1*x2=1/6