Bonsoir, quelqu'un pourrait m'aider pour le a et b svp ?

a =(x-3)(x-4) =0
x-3 =0                   x-4 =0
x =3                      x = 4

b)
x(2x+6) =0

x = 0                              2x+6 =0
                                        2x = -6
                                        x = -6/2
                                        x = -3