Answer
$(5,10)$
Work Step by Step
We know that the midpoint of the line segment whose endpoints are $(x_{1},y_{1})$ and $(x_{2},y_{2})$ is the point with coordinates $(\frac{x_{1}+x_{2}}{2},\frac{y_{1}+y_{2}}{2})$.
Therefore, a line with endpoints (3, 9) and (7, 11) will have a midpoint of $(\frac{3+7}{2},\frac{9+11}{2})=(\frac{10}{2},\frac{20}{2})=(5,10)$.
