Answer
$(-2,7)$
Work Step by Step
Step 1. Assume the coordinates of the other endpoint are $(x,y)$
Step 2. Use the formula for midpoint, we have $\frac{x+(-16)}{2}=-9$ and $\frac{y+9}{2}=8$
Step 3. Solve above equations to get $x=-2, y=7$, thus the other endpoint is $(-2,7)$
