## Introductory Algebra for College Students (7th Edition)

$$-\sqrt {64} = -8$$
The problem is asking us to find the negative square root of $64$, so, first, we find the square root of $64$: $$\sqrt {64} = 8$$ because $8 \times 8$ is $64$. Now we can add the negative sign to this result: $$-\sqrt {64} = -8$$