Triangle

[stargil2989]

In equilateral triangle ABC, AB=3x and BC= 2x+2. Find the numerical value of the perimeter of triangle ABC

 

[Unco]

You probably mean AB=3x (or AC=3x). The sides of an equilateral triangle are equal, so
AB = BC
3x = 2x + 2 (1)

Solve for x. The perimeter of the triangle is three times the length of one side. So if you use AB=3x, the perimeter is 3*3x=9x where you found a value for x from (1).