Find the sum of all possible positive integer values of b such that the quadratic equation 2x^2 + 15x + b = 0 has rational roots.
+124 2x^2 + 5x + b = 0
If b is a positive integer.......it cannot be an integer larger than 3 because the discriminant would be < 0
So......the only possible positive integer values for b are either 1, 2 or 3
If b = 1, the discriminant = √17 and this will not produce a rational solution
If b = 2, the discriminant = √9 = 3 and this will produce a rational solution
And if b = 3, the discriminant = √1 = 1 and this too will produce a rational solution
So....2,3 produce rational roots for b....where b is a positive integer
And the sum of these = 5
