The coordinates for the midpoint of [tex]ab[/tex] are [tex](-1,\frac{13}{2})[/tex].
You can use the midpoint formula (shown below) to solve this problem, by plugging in your two coordinates as [tex](x_{_1},y_{_1})[/tex] and [tex](x_{_2},y_{_2}).[/tex]
[tex]M = (\frac{x_{_1}+{x_{_2}} }{2} , \frac{y_{_1}+{y_{_2}} }{2})[/tex]
Worked out, that would be:
[tex]M = (\frac{4+(-6) }{2} , \frac{7+6}{2}) \\ \\
= (\frac{4-6 }{2} , \frac{7+6}{2}) \\ \\
= (\frac{-2 }{2} , \frac{13}{2}) \\ \\
= (-1,\frac{13}{2})[/tex]
