ex 13b
[tex]( \sqrt{3} x + 2) {}^{2} - ( \sqrt{2} x - 1)( \sqrt{2} x + 1) - (x + 2 \sqrt{3} ) {}^{2} = \\ 3x {}^{2} + 4 \sqrt{3} x + 4 - (2x {}^{2} - 1) - (x {}^{2} + 4 \sqrt{3} x + 12) = \\ 3x {}^{2} + 4 \sqrt{3} x + 4 - 2x {}^{2} + 1 - \times {}^{2} - 4 \sqrt{3} x - 12 = \\ 0 - 7 = - 7[/tex]
