Vertices(-3, -1), (-3, 4) and (9, -1)
[tex]\begin{gathered} d=\sqrt[]{(-3+3)^2+(-5)^2} \\ d=\sqrt[]{25} \\ d=5 \\ \\ d=\sqrt[]{(12)^2(0)}^2=\sqrt[]{144}=12 \\ d=\sqrt[]{(12)^2(5)^2}^{}=\sqrt[\square]{144+25}=\sqrt[]{169}=13 \end{gathered}[/tex]The longest side is 13