Problem 15: $\displaystyle \int \sqrt{12 + 4x^2}$

I get:

$\displaystyle x\sqrt{x^2 + 3}+ 3 \ln(\frac{\sqrt{x^2 + 3} + x}{\sqrt{3}})$

the book has the same answer except the radical in the denominator of the natural log part is gone. Where did I go wrong?

Thanks