# -*- coding: utf-8 -*-

import math

def quadratic(a, b, c):   
    delta = math.sqrt(b**2-4*a*c)
    ans1 = (-b+delta)/(2*a)
    ans2 = (-b-delta)/(2*a)
    return ans1, ans2

# 测试:
print('quadratic(2, 3, 1) =', quadratic(2, 3, 1))
print('quadratic(1, 3, -4) =', quadratic(1, 3, -4))

if quadratic(2, 3, 1) != (-0.5, -1.0):
    print('测试失败')
elif quadratic(1, 3, -4) != (1.0, -4.0):
    print('测试失败')
else:
    print('测试成功')