developper
b =(2x+1)²

b =4x²+4x+1

factoriser : pas la peine c est deja factoriser ou si tu preferes (2x+1)(2x+1)

résous

2x-6 =0                                2x+8 =0

2x =6                                     2x = -8

x =6/2                                       x = -8/2

x =3                                          x = -4