Question

(√2 - 1) (√2 + 3)
(√3+1)(√2+3)
(2+√8)²
(2√2-√3)²

Answer 1

$( \sqrt{2} - 1) (\sqrt{2} + 3)=\sqrt{2^2}+3\sqrt{2}-\sqrt{2}-3=2\sqrt{2}-1 \\\\(\sqrt{3}+1)(\sqrt{2}+3)=\sqrt{6}+3\sqrt{3}+\sqrt{2}+3 \\\\(2+ \sqrt{8} )^2=2^2+4 \sqrt{4.2} + \sqrt{8^2}=12+8\sqrt{2} \\\\(2\sqrt{2}-\sqrt{3})^2=2^2.\sqrt{2^2}-2.2\sqrt{2}.\sqrt{3}+\sqrt{3^2}=11-4\sqrt{6}$