Réponse:
[tex](x + 3) {}^{2} = x {}^{2} + 2 \times 3x + 3 {}^{2} \\ = x {}^{2} + 2 + 9 \times 3x \\ = x {}^{2} + 11 \times 3x[/tex]
[tex](x - 4)(x + 4) = x {}^{2} - 4 {}^{2} \\ = x {}^{2} - 16[/tex]
