If a problem asks to evaluate

$\int_{3}^{4} (2x-4)^\frac{-1}{2} dx$

and I do this:

$=[(2x-4)^\frac{1}{2}]_3^4$

And I eventually get:

$=\sqrt{4} - \sqrt{2}$

Would I get multiple answers? As:

$=\pm 2$ - $\pm \sqrt{2}$

Because the answers in my textbook say there's only one answer, which is: $2 - \sqrt{2}$

Thanks!