Change your Points of View

My:
object ChangePoint {
  def point(a: Int, b: Int):()=>List[Int]={
    ()=>List(a,b)
  }
  def fst(pt:()=>List[Int]): Int = {
    pt().head
  }
  def snd(pt:()=>List[Int]): Int = {
    pt()(1)
  }
  def sqrDist(pt1:()=>List[Int], pt2:()=>List[Int]): Int = {
    (math.pow(pt2()(0)-pt1()(0), 2)+math.pow(pt2()(1)-pt1()(1),2)).toInt
  }
  def line(pt1:()=>List[Int], pt2:()=>List[Int]): List[Int] =  List(pt1()(1)-pt2()(1),
    pt2()(0)-pt1()(0),
    pt1()(0)*pt2()(1) - pt2()(0)*pt1()(1) )
}

Other:
object ChangePoint {

  type P = () => (Int, Int)

  def point(a: Int, b: Int): P = () => (a, b)
  def fst(pt: P): Int = pt()._1
  def snd(pt: P): Int = pt()._2
  def sqrDist(pt1: P, pt2: => P): Int =
    (math.pow(fst(pt1) - fst(pt2), 2) + math.pow(snd(pt1) - snd(pt2), 2)).toInt
  def line(pt1: P, pt2: P): List[Int] = {
    val l = snd(pt1) - snd(pt2)
    val m = fst(pt2) - fst(pt1)
    val n = -(l * (fst(pt1)) + m * (snd(pt1)))
    List(l, m, n)
  }
}