Hello!
The midpoint formula is basically an average of x and y.
It is also written as: [tex](\frac{x_{1}+x_{2}} {2},\frac{y_{1}+ y_{2}} {2})[/tex].
With the formula above, we can substitute the given points into the equation, and simplify.
[tex](\frac{3 +9}{2}, \frac{9+(-2)}{2}) = (\frac{12}{2}, \frac{7}{2}) = (6, 3.5)[/tex]
Therefore, the midpoint between points H and J is choice D, (6, 3.5).
