act 1

formula_general(A, B, C) ->
  if (B * B - 4 * A * C) > 0 -> {(-B + math:sqrt(B * B - 4 * A * C)) / (2 * A), (-B - math:sqrt(B * B - 4 * A * C)) / (2 * A)}
    ; true -> imaginarias
  end.