Answer:
Side length of equilateral triangle is = 29 units
Step-by-step explanation:-
In geometry, an equilateral triangle is a triangle that has all its sides equal in length.
3 given lengths are
3x+8 , 5x - 6 , 2x +15
so,

consider 2 sides,



so,

As equilateral triangle
3x+8 = 5x - 6 = 2x +15 = 29
The sides of a triangle are straight lines that are joined by the three vertices of the triangle.
so,
Side,length of equilateral triangle is 29 units
Note :-
Number of Sides = 3
Number of angles = 3
Each interior angle = 60
Each exterior angle = 120
Perimeter = 3 times of side-length
Area = √3/ 4 x (side)2
Height = √3 (side)/2