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If 7+353+573535=p+q5\dfrac{7 + 3\sqrt{5}}{3 + \sqrt{5}} - \dfrac{7 - 3\sqrt{5}}{3 - \sqrt{5}} = p + q\sqrt{5} , find the values of p and q where p and q are rational numbers.

Rational Irrational Nos

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Answer

Since, it is given that

(7+35)3+5\dfrac{(7 + 3\sqrt{5})}{3 + \sqrt{5}} - (735)(35)\dfrac{(7 - 3\sqrt{5})} {(3 - \sqrt{5})} = p + q5\sqrt{5}

On solving,

(7+35)(35)(735)(3+5)(3+5)(35)(2175+9515)(21+759515)32(5)2(2175+9515)(21+759515)952175+95152175+95+159518514544×54=55=p+q50+1×5=p+q5\dfrac{(7 + 3\sqrt{5})(3 - \sqrt{5}) - (7 - 3\sqrt{5})(3 + \sqrt{5})}{(3 + \sqrt{5})(3 - \sqrt{5})} \\[1.5em] \Rightarrow \dfrac{(21 - 7\sqrt{5} + 9\sqrt{5} - 15) - (21 + 7\sqrt{5} - 9\sqrt{5} - 15)}{3^2 - {(\sqrt{5})}^2} \\[1.5em] \Rightarrow \dfrac{(21 - 7\sqrt{5} + 9\sqrt{5} - 15) - (21 + 7\sqrt{5} - 9\sqrt{5} - 15)}{9-5} \\[1.5em] \Rightarrow \dfrac{21 - 7\sqrt{5} + 9\sqrt{5} - 15 - 21 - 7\sqrt{5} + 9\sqrt{5} + 15}{9-5} \\[1.5em] \Rightarrow \dfrac{18{\sqrt{5}} - 14{\sqrt{5}}}{4} \\[1.5em] \Rightarrow \dfrac{4 × {\sqrt{5}}}{4} = \sqrt{5} \\[1.5em] \therefore\sqrt{5} = p + q{\sqrt{5}} \\[1.5em] \Rightarrow 0 + 1 × \sqrt{5} = p + q{\sqrt{5}}

Hence,value of p = 0 and q = 1.

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