to find an equation of the line we need only 2 points, in this case E and C. First we need to calculate the slope
[tex]m=\frac{2-0}{7-1}=\frac{2}{6}=\frac{1}{3}[/tex]having the slope, we have that
[tex]\begin{gathered} y-0=\frac{1}{3}(x-1)=\frac{1}{3}x-\frac{1}{3} \\ y=\frac{1}{3}x-\frac{1}{3} \end{gathered}[/tex]so the equation for the line that pass through A E and C is
[tex]y=\frac{1}{3}x-\frac{1}{3}[/tex]