Answer
$(-5,0)$
Work Step by Step
Since $-180^\circ=180^\circ-360^\circ$, $-180^\circ$ is the same as $180^\circ$. Use the fact that a point $r$ units from the origin with an angle $\theta$ from the horizontal is located at $(r\cos\theta,r\sin\theta)$. Using $r=5$ and $\theta=180^\circ$, the point is located at $$(5\cos(180^\circ),5\sin(180^\circ))=(-5,0)$$ Verify these trigonometric values using the unit circle if necessary.