input: def linear_eq(a: float, b: float, c: float, x: float, y: float) -> float:
      """Calculate the objective function of a linear equation of the form ax + by = c.
      >>> linear_eq(3, 5, 7, 2, 1)
      6.0
      >>> linear_eq(1, 2, 3, 4, 5)
      11.0
      """
      return a*x + b*y - c
output:     return abs(a*x + b*y - c)