I have to solve x in terms of k
$\displaystyle log x + log (x+9)=k$
I haven't taken pre calc in 3 years so my memory of it is really sketchy..this is a review problem for calc which I'm taking right now.
Log(x^2+9x)=k
10^k=(x^2+9x)
Can't really figure out where to go from there. Like I said I barely remember anything from pre calc since its been about 3 years.
That's the right way to do it, now notice that it is equal to the equation $\displaystyle x^2 + 9x - 10^k = 0$, which is a quadratic equation in $\displaystyle x$ with a constant term in $\displaystyle k$. Therefore you can apply the quadratic formula to isolate $\displaystyle x$ and solve it in terms of $\displaystyle k$.