# Homework Help: Solve log(x) + log(x+3) = 1

1. Nov 22, 2008

### HalloGubi

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

logx+log(x+3)=1

2. Relevant equations

3. The attempt at a solution

Ive tried to put it in solve so i know x=2

i think i have to, hmm i dont know if its called differantiate in english but i dont know how to differantiate log.

Edit: this is what ive tried after differantiating

1/x+1/x=1
that means it must be 2 since 2 halfs give 1

Last edited: Nov 22, 2008
2. Nov 22, 2008

### Hootenanny

Staff Emeritus
Re: logx+log(x+3)

Welcome to Physics Forums.

I'm guessing that you're trying to solve for equation to find x?

3. Nov 22, 2008

### HalloGubi

Re: logx+log(x+3)

yes, sry for my bad explaining of my problem

4. Nov 22, 2008

### Hootenanny

Staff Emeritus
Re: logx+log(x+3)

No problem.

When attempting to solve equations, usually the best thing to do is to collect all the terms you want together. So can you combine the two log terms into a single logarithm?

5. Nov 22, 2008

### Staff: Mentor

Re: logx+log(x+3)

This problem has nothing to do with differentiation. All you need to know are the properties of logarithms and how to factor quadratics.

6. Feb 5, 2011

### faoltaem

Re: logx+log(x+3)

I know this is an old post but incase people find it in the future:

rule 1)
logbx + logby = logbxy

rule 2)
x (x + a) = x2 + ax

rule 3)