Answer:
57 units
Explanation:
You want to know the perimeter of an equilateral triangle with sides marked (x+12), (2x+5), and (3x-2).
Value of x
Since the sides are marked as the same length, we can equate the expressions for the side lengths:
2x +5 = x +12
x = 7 . . . . . . . . subtract x+5
Perimeter
Then the length of each side of the triangle is ...
x +12 = 7 +12 = 19
The perimeter of the equilateral triangle is 3·19 = 57 units.