input: def linear_eq(a: float, b: float, c: float, x: float, y: float) -> float:
      """ Calculates the objective function of a linear equation given the coefficients a, b, and c,
      and the values x and y.
      >>> linear_eq(3, 5, 7, 2, 1)
      4.0
      >>> linear_eq(1, 1, 5, 3, 2)
      0.0
      >>> linear_eq(2, 2, 6, 1, 1)
      2.0
      """
output:     return abs(a * x + b * y + c) / (a**2 + b**2)**0.5