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

import math

def quadratic(a,b,c):
    if (b**2-4*a*c) < 0:
        return '该方程无解'
    elif a ==  0:
        return 'a不能为0'
    else:
        x1 = (-b + math.sqrt(b*b-4*a*c))/(2*a)
        x2 = (-b - math.sqrt(b*b-4*a*c))/(2*a)
    return x1,x2

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