Hey guys,

log(x+3) - logx = 1

so I got 1 = (x+3) / (x)

and the book says the answer is 1/3

I don't know how it got this :(

any help? Thanks

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- May 18th 2013, 02:48 PMCakeExponential and Logarithmic Equations
Hey guys,

log(x+3) - logx = 1

so I got 1 = (x+3) / (x)

and the book says the answer is 1/3

I don't know how it got this :(

any help? Thanks - May 18th 2013, 02:55 PMHallsofIvyRe: Exponential and Logarithmic Equations
Is that the common logarithm? Base 10? If so then you have $\displaystyle log(x+3)- log(x)= log\left(\frac{x+ 3}{x}\right)= 1$ and then "get rid of" the logarithm by taking 10 to the power of each side. Instead of getting $\displaystyle \frac{x+ 3}{x}= 1$ you should have $\displaystyle \frac{x+ 3}{x}= 10^1= 10$.

Can you solve $\displaystyle \frac{x+ 3}{x}= 10$? - May 18th 2013, 03:01 PMPlatoRe: Exponential and Logarithmic Equations
- May 18th 2013, 03:06 PMCakeRe: Exponential and Logarithmic Equations
Correct, it is base 10. Ahh I see. So whenever I have " = 1 " and with a base of 10. It automatically equals to 10^1?

and yes, thank you. That gives me 1 / 3. Thanks a lot for clearing this up. I would have never gotten this.