(i) Given,
523
Let us rationalise the denominator,
⇒5×523×5⇒(5)2215⇒5215
Hence,523=5215
(ii) Given, 6+56−5
Let us rationalise the denominator,
⇒(6+5)×(6−5)(6−5)×(6−5)=(6)2−(5)2(6−5)2=6−5(6)2+(5)2−2×6×5=16+5−2×30=11−230
Hence, 6+56−5=11−230.