(2 - \(\sqrt{3}\))( \(\sqrt{3}\) + 1) = 2\(\sqrt{3}\) + 2 - 3 - \(\sqrt{3}\) = \(\sqrt{3}\) - 1
( \(\sqrt{2}\) + \(\sqrt{5}\))(2\(\sqrt{2}\) - \(\sqrt{5}\)) = 2 \cdot 2 - \(\sqrt{10}\) + 2\(\sqrt{10}\) - 5 = 4 + \(\sqrt{10}\) - 5 = \(\sqrt{10}\) - 1
(a + \(\sqrt{b}\))(a - \(\sqrt{b}\)) = a^2 - (\(\sqrt{b}\))^2 = a^2 - b
( \(\sqrt{b}\) - \(\sqrt{c}\))( \(\sqrt{b}\) + \(\sqrt{c}\)) = (\(\sqrt{b}\))^2 - (\(\sqrt{c}\))^2 = b - c
(4 + \(\sqrt{3}\))(4 - \(\sqrt{3}\)) = 16 - 3 = 13
(y - \(\sqrt{7}\))(y + \(\sqrt{7}\)) = y^2 - 7
(4\(\sqrt{2}\) - 2\(\sqrt{3}\))(2\(\sqrt{3}\) + 4\(\sqrt{2}\)) = 4 \cdot 4 \cdot 2 - 4 \(\sqrt{6}\) + 4 \(\sqrt{6}\) - 4 \cdot 3 = 32 - 12 = 20
(m + \(\sqrt{n}\))^2 = m^2 + 2m\(\sqrt{n}\) + n
( \(\sqrt{a}\) - \(\sqrt{b}\))^2 = a - 2\(\sqrt{ab}\) + b
(2 - 3\(\sqrt{3}\))^2 = 4 - 12\(\sqrt{3}\) + 9 \cdot 3 = 4 - 12\(\sqrt{3}\) + 27 = 31 - 12\(\sqrt{3}\)