Answer
See below.
Work Step by Step
The distance formula from $P_1(x_1,y_1)$ to $P_2(x_2,y_2)$ is $d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$.
The midpoint $M$ of the line segment from $P_1(x_1,y_1)$ to $P_2(x_2,y_2)$ is: $(\frac{x_1+x_2}{2},\frac{y_1+y_2}{2})$.
Hence:
a) $d=\sqrt{(4-(-1))^2+(-2-3)^2}=\sqrt{25+25}=\sqrt{50}=5\sqrt2.$
b)$M=(\frac{-1+4}{2},\frac{3+(-2)}{2})=(1.5,0.5)$.
