Triangle ΔGLF Is Isosceles, And Its Perimeter Is 25. The Two Equal Sides Are Twice As Long As The Base. What Is The Length Of Each Side?

Let s represent the side length and b represent the base length.
2s + b = 25    (the perimeter is 25)
s = 2b    (sides are twice as long as the base)

2(2b) + b = 25    (substituting for s)
5b = 25    (collect terms)
b = 5    (divide both sides by 5)
s = 2(5) = 10

The length of each side is 10, the length of the base is 5.