Type inference + Function overloading

QuadraticEquationSolver.scala

object QuadraticEquationSolver {
  def solve(a: Double, b: Double, c: Double) = {
    val discriminant = b*b - 4*a*c
    if (discriminant < 0)
      List()
    else {
      val sqrtOfDisr = math.sqrt(discriminant)
      List((-b - sqrtOfDisr)/2, (-b + sqrtOfDisr)/2)
    }
  }

  def main(args: Array[String]) {
    val x1 = -2
    val x2 = 3
    val a = 1
    val b = -(x1 + x2)
    val c = x1*x2
    println("roots: " + solve(a, b, c) + ", expected: (" + x1 + ", " + x2 + ")")
  }
}