请问为什么不对这个
import math
def quadratic_equation(a, b, c):
if b*b-4*a*c > 0:
x=(-b+math.sqrt(b*b-4*a*c))/(2*a)
y=(-b-math.sqrt(b*b-4*a*c))/(2*a)
return x,y
elif b*b-4*a*c==0:
return (-b)/(2*a)
else :
return '无解'
print quadratic_equation(2, 3, 0)
print quadratic_equation(1, -6, 5)
