What is the sum of the coordinates of the midpoint of the line segment connecting points $(5,4)$ and $(-9,8)$?
To find the midpoint of a line segment, I need to average the x-coordinates and the y-coordinates of the endpoints. That means the midpoint has coordinates $\left(\frac{5 + (-9)}{2}, \frac{4 + 8}{2}\right)$. Simplifying the fractions, I get $\left(-2, 6\right)$ as the midpoint. To find the sum of the coordinates, I just need to add the x-value and the y-value. So the sum is $-2 + 6 = 4$. 