+478 Find the constant k such that the quadratic 2x^2 + 3x + 8x - x^2 + 4x + k has a double root.
+37165 The disciminant b^2 - 4ac must = 0 for this to be true
Simplify to x^2 + 15x + k then comute the discriminant
15^2 - 4 (1)(k) = 0
4k = 225
k = 56.25
