input: def solve_linear_equation_system(a: float, b: float, c: float):
      """
      Solve a linear equation system of the form: ax + by = c.
      Return the values of x and y as a tuple.
      >>> solve_linear_equation_system(2, 1, 4)
      (2.0, 2.0)
      """
output:     if a == 0 and b == 0:
          raise ValueError("The coefficients a and b cannot both be zero.")
      if a == 0:
          return (0.0, c / b)
      if b == 0:
          return (c / a, 0.0)
      return (c / a, 0.0)