Bonsoir, Résoudre dans IR: a) x²-9=0 b) (x-5)²=49

Bonsoir

X^2 -9 = 0

(X-3)(x3) = 0

X-3=0

X =3

X+3=0

X = -3

(X-5)^2 =49

(X-5)^2-49=0

(X-5)^2 -7^2 =0

(X-5-7)(x-5+7)=0

(X-12)(x+2) =0

X-12 = 0

X =12

X+2 =0

X = -2