how do i find the perimeter of a triangle with no given sides

Question

i have a triangle with all equal sides but all the sides are unknown and one side is (21-x) another side is (2x-3) and the third side is (x+5)

Answer 1

If it is known that all sides are equal it must be true that 2x - 3 = x + 5, as one of the choices. Solve that equation for x. Plug the value for x into the expression for each of the sides to confirm that indeed all the sides are equal. If that proves to be the case, multiply one of the side lengths by 3 to get the perimeter.

Answer 2

If the sides are equal then x+5 would equal 2x-3 . Solving for x you would get x=8

So x+5= 8+5=13

2x-3 = 16-3=13

21–x= 21-8=13

There you go