input: def linear_eq(a: float, b: float, c: float, x: float, y: float) -> float:
      """ Compute the objective function of a linear equation ax + by = c.
      >>> linear_eq(3, 5, 7, 1, 1)
      1.0
      >>> linear_eq(3, 5, 7, 2, 2)
      3.0
      """
      return a * x + b * y - c
output:     return abs(a * x + b * y - c)