Chapter 1 - Tools of Geometry - 1-7 Midpoint and Distance in the Coordinate Plane - Got It? - Page 51: 2

$(11,-13)$

Use the midpoint formula to find $x_2$. $M=\frac{x_1+x_2}{2}$ $4=\frac{-3+x_2}{2}$ $4\times2=\frac{-3+x_2}{2}\times2$ $8=-3+x_2$ $8+3=-3+x_2+3$ $11=x_2$ Use the midpoint formula to find $y_2$. $M=\frac{y_1+y_2}{2}$ $-9=\frac{-5+y_2}{2}$ $-9\times2=\frac{-5+y_2}{2}\times2$ $-18=-5+y_2$ $-18+5=-5+y_2+5$ $-13=y_2$