Question

tell me the answer of questions no 23

Answer 1

$\frac{2 - \sqrt{5} }{2 + 3 \sqrt{5} } = \sqrt{5} a + b \\ now \\ \frac{(2 - \sqrt{5} )( 3 \sqrt{5} - 2 )}{(2 + 3 \sqrt{5})( 3 \sqrt{5} - 2) } = \frac{ 6 \sqrt{5} - 4 + 2 \sqrt{5} - 15}{ {(3 \sqrt{5} )}^{2} - {2}^{2} } \\ = \frac{8 \sqrt{5} - 19}{41} = + \frac{8}{41} \sqrt{5} - \frac{19}{41}$
ѕσ α= 8/41. αnd. в = -19/41

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σr pαrt ....
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х = 7-4√3

$\frac{1}{x} = \frac{1}{7 - 4 \sqrt{3} } = \frac{7 + 4 \sqrt{3} }{(7 - 4 \sqrt{3})(7 + 4 \sqrt{3} ) } \\ = \frac{7 + 4 \sqrt{3} }{ {7}^{2} - {(4 \sqrt{3} )}^{2} } \\ = \frac{ 7 + 4\sqrt{3} }{49 - 48} \\ = 7 + 4 \sqrt{3}$
ѕσ ..
(х +1/х)² =(7-4√3 +7+4√3)²

=14² =196__αnѕwєr__

hσpє thєѕє αrє ur rєquíєd αnѕwєr.

prσud tσ hєlp u