Réponse:
[tex](2x) {?}^{2} + 2 \times 2x \times 3 + 3 {?}^{2} - (2x \times 2x - 2x \times 1 + 1 \times 2x - 1 \times 1)[/tex]
[tex]4x {}^{2} + 12x + 9 - 4x {?}^{2} + 2x + 2x - 1[/tex]
[tex]4x {?}^{2} - 4x {?}^{2} + 12x + 2x + 2x + 9 - 1[/tex]
[tex]0 + 16x + 8[/tex]
