le 40 et 41 s'il vous plait

40/
a)
x²+5-54 =0
x²-49 =0
(x-7)(x+7) =0

x-7 =0                 x+7 =0
x = 7                    x = -7

b)
t² -7 = 74
t²-7-74 =0
t²-81 =0
(t-9)(t+9) =0

t-9 =0                       t+9 =0
t = 9                          t = -9

je te laisse faire la c

41/

2x² = 18
2x²-18 =0
2(x²-9) =0
2(x-3)(x+3) =0

x-3 =0                          x+3 =0
x =3                             x = -3

b)

1/3y² = 27
1/3y²-27 =0
3(1/9y²-9) =0
3(1/3y-3)(1/3y+3) =0

1/3y -3 =0                                   1/3y +3 =0
1/3y =3                                         1/3y = -3
y = 3x3                                              y = -3x3
y = 9                                                 y = -9

je te laisse faire la derniere meme raisonnement