We can calculate the coordinates of a midpoint between two points as the average of the coordinates of this points.
Then, it can be written for x as:
[tex]x=\frac{x_1+x_2}{2}=\frac{\frac{7}{3}+(\frac{-1}{3})}{2}=\frac{6}{3}\cdot\frac{1}{2}=\frac{6}{6}=1[/tex]and for y:
[tex]y=\frac{y_1+y_2}{2}=\frac{\frac{5}{9}+\frac{7}{9}}{2}=\frac{12}{9}\cdot\frac{1}{2}=\frac{12}{18}=\frac{2}{3}[/tex]The midpoint is (x,y) = (1, 2/3)
