def quadratic(a,b,c):
    import math
    if (b*b-4*a*c)>0:
        n=math.sqrt(b*b-4*a*c)
        x1=(-b+n)/(2*a)
        x2=(-b-n)/(2*a)
        print('方程的根为%s,%s'%(x1,x2))
    elif (b*b-4*a*c)==0:
        x=-b/(2*a)
        print('方程根为%s'%x)
    elif (b*b-4*a*c)<0:
        print('此方程无实根')