Answer:
28
Explanation:
The diagram shows a square, and it is known that all side lengths for a square are equal. We can use these information on hand and write the following equation to find the side length:
7x + 3 = 5x + 8 transfer like terms to the same side of the equation
7x - 5x = 8 - 3 add/subtract
2x = 5 divide both sides by 2
x = 2.5 to find a side length simply replace x with 2.5
5x + 8 = 5*(2.5) + 8
5*(2.5) + 8 = 28