ERROR, Second degree resolver

from math import sqrt


a = int(input("a"))
b = int(input("b"))
c = int(input("c"))


print(a,"x²+",b,"x+",c,"=0")

d = int((b**)-4*a*c)

if d < 0:
    print("Pas de racines")

if d == 0:
    print("Une racine: ",(-b)/2*a)

if d > 0:
    x1 = (-b-sqrt(d))/2*a
    x2 = (-b+sqrt(d))/2*a
    print("Deux racines: x1= ",x1," et x2 = ",x2)