If two angle of a triangle are congruent , then sides of opposite those angle are congruent Then in triangle ABC is:
[tex]AC=AB[/tex][tex]\begin{gathered} AC=AB \\ 2x+7=4x-7 \\ 4x-2x=7+7 \\ 2x=14 \\ x=\frac{14}{2} \\ x=7 \end{gathered}[/tex]
So the large side is BC:
[tex]\begin{gathered} BC=4x \\ BC=4\times7 \\ BC=28 \end{gathered}[/tex]
