Réponse :
Explications étape par étape
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x^2 - 49 = 0
x^2 - 7^2 = 0
(x - 7)(x + 7) = 0
x - 7 = 0 ou x + 7 = 0
x = 7 ou x = -7
x^2 = 100
x^2 = 10^2
x^2 - 10^2 = 0
(x - 10)(x + 10) = 0
x - 10 = 0 ou x + 10 = 0
x = 10 ou x = -10
2x^2 = 128
x^2 = 128/2
x^2 = 64
x^2 - 64 = 0
x^2 - 8^2 = 0
(x - 8)(x + 8) = 0
x - 8 = 0 ou x + 8 = 0
x = 8 ou x = -8
x^2 = 5
x^2 - 5 = 0
x^2 - (V5)^2 = 0
(x - V5)(x + V5) = 0
x - V5 = 0 ou x + V5 = 0
x = V5 ou x = -V5
x^2 - 36 + (2x + 3)(x - 6) = 0
x^2 - 6^2 + (2x + 3)(x - 6) = 0
(x - 6)(x + 6) + (2x + 3)(x - 6) = 0
(x - 6)(x + 6 + 2x + 3) = 0
(x - 6)(3x + 9) = 0
(x - 6) * 3(x + 3) = 0
3(x - 6)(x + 3) = 0
x - 6 = 0 ou x + 3 = 0
x = 6 ou x = -3
x^2 - 9 - (2x + 1)(x + 3) = 0
x^2 - 3^2 - (2x + 1)(x + 3) = 0
(x - 3)(x + 3) - (2x + 1)(x + 3) = 0
(x + 3)(x - 3 - 2x - 1) = 0
(x + 3)(-x - 4) = 0
x + 3 = 0 ou -x - 4 = 0
x = -3 ou x = -4
