input: from typing import Tuple
  
  def linear_eq(a: int, b: int, c: int, x: float, y: float) -> float:
      """
      Calculate the objective function of a linear equation in the form: ax + by - c.
      >>> linear_eq(3, 5, 7, 2, 1)
      1.0
      >>> linear_eq(2, 3, 6, 1, 2)
      2.0
      """
      return a*x + b*y - c
output:     return float(a*x + b*y - c)