+1286 Find the constant k such that the quadratic 2x^2 + 3x + 8x - x^2 + 4x + k has a double root.
+37147 First , simplify this equation to:
x^2 + 15x + k = 0 Where a = 1 b = 15 c = k
if the discriminant (b^2 - 4ac) is equal to zero, it will be a 'double root'
b^2 - 4ac = 0
15^2 - 4 (1)(k) = 0
225 = 4k
k = 225/4
