[tex](2+\sqrt{3})^{2}=2^{2}+2\cdot2\cdot\sqrt{3}+(\sqrt{3})^{2}=\\
\\ =4+4\sqrt{3}+3=\\
\\ =7+4\sqrt{3}\\
\\ \\
\\ (1-2\sqrt{3})^{2}=1^{2}-2\cdot1\cdot2\sqrt{3}+(2\sqrt{3})^{2}=\\
\\ =1-4\sqrt{3}+2^{2}\cdot(\sqrt{3})^{2}=\\
\\ =1-4\sqrt{3}+4\cdot3=\\
\\ =1-4\sqrt{3}+12=\\
\\ =13-4\sqrt{3}\\
\\
\\
\\ \boxed{(a \pm b)^{2}=a^{2} \pm 2ab +b^{2}}
[/tex]
