input: 
  def solve_linear_equation_system(a: int, b: int, c: int) -> tuple:
      """
      Solve a linear equation system of the form: ax + by = c
      
      >>> solve_linear_equation_system(2, 1, 4)
      (2.0, 2.0)
      """
      x = (c - b) / a
      y = (c - a * x) / b
      return x, y
  
output:     if a == 0 and b == 0:
          raise ValueError("Both coefficients a and b cannot be zero.")
      if a == 0:
          y = c / b
          return None, y
      if b == 0:
          x = c / a
          return x, None
      x = (c - b) / a
      y = (c - a * x) / b
      return x, y