Answer:
As in an equilateral triangle all sides are equal so 9+3x = 5x-5
9+3x = 5x-5
9+5 = 5x-3x
14 = 2x
14/2 = x
7= x
So,As we know that x is 15 so we can substitute the values 9+3x or 5x-5
9+3x
=9+3*7
=30
So, one side of the triangle = 30
Perimeter of an equilateral triangle = 3*side
=3*30 = 90
So, perimeter of the equilateral triangle = 90
