# Homework Help: Another log equation

1. Nov 14, 2008

### nikita33

1. The problem statement, all variables and given/known data

log x2 + log x - log 2.7 = log 10
solve for x

2. Relevant equations

3. The attempt at a solution
this one i really dont know how to do. I cant find any examples, but this is what i tried (youre gonna be like, what? but i had to attempt it.) I think when logs are in addition format, youre supposed to multiply them? does that make sense? i really need help on this one. :

2 log x + log x = log 10 + log 2.7
2 log x2 = log 27
4 log x = log 27

thats as far as i can get. i know its wrong. even one step in the right direction would help me.

2. Nov 14, 2008

### Dick

No, 2*log(x)+log(x) IS NOT 2*log(x^2). 2*log(x)+log(x)=3*log(x)=log(27). Try it from there. Or do log(x^2)+log(x)=log(x^3)=log(27).

Last edited: Nov 14, 2008
3. Nov 14, 2008

### nikita33

^
i had it that way the first time. i think i changed it because i got

3 log x = log 27
then to solve for x i got something that looks like this:

x = log 27/3 log

3 log? is it supposed to be 3 log 1?

if so, the answer is 0. i put 0 on my exam, although i set it up incorrectly. my prof would give a point for the correct answer and i got no points, so i dont think thats the answer.

4. Nov 14, 2008

### Staff: Mentor

"3 log" makes no sense. Go back a step to 3 log x = log 27.

What's another way to write 3 log x?

5. Nov 14, 2008

### Dick

3*log(x)=log(x^3), doesn't it? 3log(x) is not 3*log*x. That's just plain silly, as Mark44 points out.