Quadratic Equation Solution Set

I'm working on basic problems to review for a placement test into calculus. The questions are here, I don't need you to click on if your not interest, they are multiple choice. College Algebra

Where am I going wrong here?

$\displaystyle x^2-2x-24=24$

$\displaystyle x^2-2x-48=0$

$\displaystyle x=\frac{-(-2)\pm\sqrt{(-2)^2-4(-48)(1)}}{2}=\frac{2\pm\sqrt{4+182}}{2}=\frac{2\pm\ sqrt{186}}{2}$

The solution sets (in the multiple coice) are all whole numbers. I have$\displaystyle \pm\frac{\sqrt{186}}{2}\approx6.819$

Where am I going wrong here?