Chapter B, Problem 55E

$\left(a\right)$

To determine

The mid-points of the line segment joining the points $\left(1,3\right)\text{ and }\left(7,15\right)$ .

$\left(b\right)$

To determine

The mid-points of the line segment joining the points $\left(-1,6\right)\text{ and }\left(8,-12\right)$ .