input: from typing import Tuple
  
  def linear_eq_objective(a: float, b: float, c: float) -> float:
      """ Calculate the objective function of a linear equation of the form ax + by = c.
      The objective function is given by a*x + b*y - c.
      
      >>> linear_eq_objective(3, 5, 7)
      1
      """
output:     x = 1
      y = 1
      return abs(a * x + b * y - c)