为什么算不出正确答案呢?
import math
def quadratic_equation(a, b, c):
y1 = (-b) /(2*a) +( math.sqrt(b*b-4*a*c))/(2*a)
y2 = (-b) /(2*a) - (math.sqrt(b*b-4*a*c))/(2*a)
return y1,y2
print quadratic_equation(2, 3, 0)
print quadratic_equation(1, -6, 5)