Chapter 2 - Linear and Quadratic Functions - Section 2.3 Quadratic Functions and Their Zeros - 2.3 Assess Your Understanding - Page 148: 123

$(-4, 1.5)$

Given: $P_{1}=(-10,4)=\left(x_{1}, y_{1}\right)$ $P_{2}=(2,-1)=\left(x_{2}, y_{2}\right)$ Use the midpoint formula $=\left(\dfrac{x_{1}+x_{2}}{2}, \dfrac{y_{1}+y_{2}}{2}\right)$ to obtain: $\begin{aligned}&=\left(\frac{-10+2}{2}, \frac{4-1}{2}\right)\\ \\&=\left(-\frac{8}{2}, \frac{3}{2}\right)\\ \\ &=(-4, 1.5) \end{aligned}$