input: 
  def linear_eq(a: float, b: float, c: float):
      """Calculates the objective function of a linear equation with coefficients a, b, and c.
      
      >>> linear_eq(3, 5, 7)
      -7.0
      """
      return a * x + b * y - c
  
output:     x = 1.0
      y = 1.0
      return a * x + b * y - c