# -*- coding: utf-8 -*-import math
def quadratic(a,b,c):
    global x1
    global x2
    if a==0:
         x=(-c)/b
         print('非二元一次方程x=',x)
    elif a<0:
        print('错误')
    elif b**2-4*a*c<0:
        print('无解')
    else:
        x1=(-b+math.sqrt(b**2-4*a*c))/(2*a)
        x2=(-b-math.sqrt(b**2-4*a*c))/(2*a)
        print('x1=', x1, 'x2=', x2)
a=float(input('a:'))
b=float(input('b:'))
c=float(input('c:'))
quadratic(a,b,c)