If the triangle is equilateral it means all the sides are the same length.
A triangle has three sides. if each side is 2/8cm then the total perimeter if 3*2/8 = 6/8 = 3/4
You can just simplify to make an equivalent equation:
(2)(3x + 8) = 5 ⇒ 6x + 16 = 5
Answer:

Hope it helped,
BioTeacher101
<em>(If you have any questions feel free to ask them in the comments)</em>
The correct answer is -15 because the absolute value is 15 but there is a negative outside the absolute value lines making it negative :)