Math, asked by BrundansaiCH, 6 hours ago

pls help me with the problem of rational numbers

sole for a and b.


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Answered by Anonymous
68

 \frac{3 -  \sqrt{5} }{3 + 2 \sqrt{5} }  = a \sqrt{5}  - b \\  \\  =  \frac{3  -  \sqrt{5} }{3 + 2 \sqrt{5} }  \times  \frac{3 - 2 \sqrt{5} }{3 - 2 \sqrt{5} }  \\  \\  =  \frac{(3 -  \sqrt{5})(3 - 2 \sqrt{5} ) }{(3 + 2 \sqrt{5})(3 - 2 \sqrt{5)} }  \\  \\  =  \frac{3(3 - 2 \sqrt{5 } ) -  \sqrt{5} (3 - 2 \sqrt{5} )}{ {3}^{2} -  ({2 \sqrt{5} )}^{2}   }  \\  \\  =  \frac{ {3}^{2}  - 6 \sqrt{5}  - 3 \sqrt{5}  + 2(5)}{9 - 4(5)}  \\  \\  =  \frac{9 - 9 \sqrt{5}  + 10}{9 - 20}  \\  \\  =  \frac{19 - 9 \sqrt{5} }{ - 11}  \\  \\  =  \frac{ - (19 - 9 \sqrt{5}) }{11}  \\  \\  =  \frac{ - 19 + 9 \sqrt{5} }{11}  \\  \\  =  \frac{9 \sqrt{5} - 19 }{11}  \\  \\  =   \frac{ 9 \sqrt{5} }{11}  -  \frac{19}{11}  \\  \\  = a \sqrt{5}  -  \frac{19}{11}   \\  \\ ∴, \: a =   \frac{9}{11}  \\   \\

if it is \frac{a \sqrt{5}  - 19}{11}

then a = 9

But ATQ,

\frac{a \sqrt{5}  - 19}{11}

So, \frac{19}{11}

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#NAWABZAADI

Answered by tashfinnoor786
1

Answer:

you can prefer above answer, suneo

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