Find the domain of $\sqrt{6-x-x^2}$.
First, we simplify the expression: $$\sqrt{6-x-x^2}=\sqrt{(2-x)(3+x)}$$ The expression inside the square root must be non-negative. The quadratic changes signs at the roots $2$ and $-3$ and is positive between the two values. Therefore, the domain of the expression is $\boxed{[-3,2]}$.