input: Write a python function to solve the quadratic equation ax**2 + bx + c = 0.
  assert solve_quadratic(1, -5, 6) == (2.0, 3.0)
  assert solve_quadratic(1, -3, 2) == (1.0, 2.0)
  assert solve_quadratic(1, -2, 1) == (1.0, 1.0)
output: def solve_quadratic(a, b, c):
      import cmath
      d = b**2 - 4*a*c
      sol1 = (-b - cmath.sqrt(d)) / (2*a)
      sol2 = (-b + cmath.sqrt(d)) / (2*a)
      if sol1 == sol2:
          return (sol1.real, sol2.real)
      else:
          return (min(sol1.real, sol2.real), max(sol1.real, sol2.real))