import math

def quadratic(a, b, c):

deta = b*b - 4*a*c

if (a == 0):

    print("此方程组不是一元二次方程组，x = %.2f。" %(-c/b))

    return

elif (deta < 0):

    print("无实解！")

    return

elif (deta == 0):

    x = -b/2*a

    print("此一元二次方程组有两个相同的解，x1 = x2 = %.2f。" %x)

    return(x)

else:

    x1 = (-b + math.sqrt(deta))/2*a

    x2 = (-b - math.sqrt(deta))/2*a

    print("此一元二次方程组有两个不相同的解，x1 = %.2f, x2 = %.2f。" %(x1,x2))

    return(x1,x2)

print(quadratic(4,8,2))

数学不好抄的作业.. :)