input: Write a python function to solve the quadratic equation for "x".
  assert solve_equation(4, 7, -5) == (1.5, -2.5)
  assert solve_equation(1, -3, 2) == (2.0, 1.0)
  assert solve_equation(1, -2, 1) == (1.0, 1.0)
output: def solve_equation(a, b, c):
      import math
      discriminant = b**2 - 4*a*c
      if discriminant >= 0:
          x1 = (-b + math.sqrt(discriminant)) / (2*a)
          x2 = (-b - math.sqrt(discriminant)) / (2*a)
          return (x1, x2) if x1 >= x2 else (x2, x1)