Respuesta :

Since we don’t know the height of base or angles. We do know it is isosceles triangle.
x+4=3x-8
x-3x= -8-4
-2x= -12 multiply both sides by -1
2x=12
x=12/2
x=6
x+4=6+4=10
3x-8=3•6-8=18-8=10
Base equals x. x=10
AC=10