The perimeter of an equilateral triangle exceeds the perimeter of a square by 1989cm. The length of each side of the triangle exceeds the length of each side of the square by d cm. The square has perimter greater than 0. How many positive integers are not possible values for d?
t for side of triangle s for side of square
3t = 4s + 1989
t - s = d
t= s +d
3s + 3d = 4s + 1989
3d = s + 1989
d = s/3 + 663
it doesn't seem to make sense.
Pls help.