input: from typing import Tuple
  
  def linear_eq(a: int, b: int, c: int, x: int, y: int) -> int:
      """
      Calculate the objective function of a linear equation of the form ax + by = c.
      >>> linear_eq(3, 5, 7, 1, 1)
      1
      >>> linear_eq(3, 5, 7, 2, 0)
      6
      >>> linear_eq(3, 5, 7, 0, 2)
      3
      """
      return a * x + b * y - c
output:     return a * x + b * y - c