Using binomial theorem the expression (a + b)6 and (a – b)6, can be expanded
(a + b)6 = 6C0 a6 + 6C1 a5 b + 6C2 a4 b2 + 6C3 a3 b3 + 6C4 a2 b4 + 6C5 a b5 + 6C6 b6
(a – b)6 = 6C0 a6 – 6C1 a5 b + 6C2 a4 b2 – 6C3 a3 b3 + 6C4 a2 b4 – 6C5 a b5 + 6C6 b6
Now (a + b)6 – (a – b)6 =6C0 a6 + 6C1 a5 b + 6C2 a4 b2 + 6C3 a3 b3 + 6C4 a2 b4 + 6C5 a b5 + 6C6 b6 – [6C0 a6 – 6C1 a5 b + 6C2 a4 b2 – 6C3 a3 b3 + 6C4 a2 b4 – 6C5 a b5 + 6C6 b6]
Now by substituting a = \( \sqrt{3}\) and b =\( \sqrt{2}\) we get
\( (\sqrt{3} + \sqrt{2})^6 -(\sqrt{3} - \sqrt{2})^6\)
= \( 2 [6 (\sqrt{3})^5 (\sqrt{2}) + 20 (\sqrt{3})^3 (\sqrt{2})^3 + 6 (\sqrt{3}) (\sqrt{2})^5]\)
= \( 2 [54(\sqrt{6}) + 120 (\sqrt{6}) + 24 \sqrt{6}]\)
= \( 2 (\sqrt{6}) (198)\)
= \( 396 \sqrt{6}\)
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