log(2x)+log(3y)-log(2z) 怎么化简?log3(x^2-2x-6)=2 log(3x+6)=1+log(x)求解,求每步详...

题目

log(2x)+log(3y)-log(2z) 怎么化简?log3(x^2-2x-6)=2 log(3x+6)=1+log(x)求解,求每步详...
log(2x)+log(3y)-log(2z) 怎么化简?log3(x^2-2x-6)=2 log(3x+6)=1+log(x)求解,

答案

log(2x)+log(3y)-log(2z)=log(3xy/z)
log3(x^2-2x-6)=2
log3(x^2-2x-6)=log3(9)
x^2-2x-6=9
x=-3 或 x=5
log(3x+6)=1+log(x)=log(10x)
3x+6=10x
x=6/7