How do you find the perimeter of an equilateral triangle that has variables in on three sides?

Question

One side of the triangle is 7x-17, another side is 4x-5, and the final side is 2x+3. How do I go about finding the perimeter of this equilateral triangle.

Answer 1

Since it's an equilateral triangle, all the sides are equal length.  So just set two of them equal and solve for x:

 

7x-17 = 4x-5

3x = 12

x = 4

 

Check:

7x-17 = 7(4)-17 = 11

4x-5 = 4(4) - 5 = 11

2x+3 = 2(4) + 3 = 11

Check - all sides are the same length!