bonsoir ,
[tex](x + \sqrt{3} ) {}^{2} + (x - \sqrt{3} ) {}^{2} \\ x {}^{2} + 2 \times x \times \sqrt{3} + \sqrt{3} {}^{2} + x {}^{2} - 2 \times x \times \sqrt{3} + \sqrt{3} {}^{2} \\ x {}^{2} + 2x \sqrt{3} + 3 + x {}^{2} - 2x \sqrt{3} + 3 \\ 2x {}^{2} + 6[/tex]