Answer :
[tex]\begin{gathered} \text{the distance between two points is } \\ d(X,Y)=\sqrt[]{(x_1-y_1)^2+(x_2-y_2_{})^2} \\ \text{now, X = (-1,-3) and Y=(4,9)} \\ d(X,Y)=\sqrt[]{(-1-4)^2+(-3-9)^2} \\ =\sqrt[]{(-5)^2+(-12)^2} \\ =\sqrt[]{25+144} \\ =\sqrt[]{169} \\ =13 \\ \\ d(X,Y)=13 \end{gathered}[/tex][tex]\begin{gathered} \text{And the midpoint between two points is } \\ M=\frac{X+Y}{2} \\ M=\frac{(-1,-3)+(4,9)}{2} \\ M=\frac{(-1+4,-3+9)}{2} \\ M=\frac{(3,6)}{2} \\ M=(\frac{3}{2},\frac{6}{2}) \\ M=(1.5,3) \end{gathered}[/tex]