Math, asked by noora35, 1 year ago

answer this question plz hurry

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Answered by Anonymous
7
First of all rationalising

 \frac{2 \sqrt{5}  +  \sqrt{3} }{2 \sqrt{5} - 3 }  \\   \\ =  >  \frac{2 \sqrt{5} +  \sqrt{3}  }{2 \sqrt{5}  -  \sqrt{3} }  \times  \frac{2 \sqrt{5} +  \sqrt{3}  }{2 \sqrt{5}  +  \sqrt{3} }  \\ \\   =  >  \frac{(2 \sqrt{5}  +  \sqrt{3} ) {}^{2} }{( 2\sqrt{5}) {}^{2}  - ( \sqrt{3}) {}^{2}   }  \\  \\  =  >  \frac{(2 \sqrt{5}) {}^{2}  + ( \sqrt{3}) {}^{2}    + 2(2 \sqrt{5} )( \sqrt{3} )}{20 - 3}  \\  \\  =  >  \frac{20 + 3 + 4 \sqrt{15} }{17}
Similarly,

 \frac{2 \sqrt{5}  -  \sqrt{3} }{2 \sqrt{5}  +  \sqrt{3} }  \\  \\  =  \frac{2 \sqrt{5} -  \sqrt{3}  }{2 \sqrt{5}  +  \sqrt{3} }  \times  \frac{2 \sqrt{5} -  \sqrt{3}  }{2 \sqrt{5} - \sqrt{3} }  \\  \\  =   \frac{(2 \sqrt{5} -  \sqrt{3} ) {}^{2}  }{(2 \sqrt{5}) {}^{2}  - ( \sqrt{3}) {}^{2}   }  \\  \\  =  >  \frac{20 + 3 - 4 \sqrt{15} }{17}
adding them, we get

 \frac{20 + 3 + 4 \sqrt{15} }{17}  +  \frac{20 + 3 - 4 \sqrt{15} }{17}  \\
=
 \frac{23 + 23 + 4 \sqrt{15} - 4 \sqrt{15}  }{17}  \\  =  >  \frac{46}{17}  = a + b \sqrt{15}
comparing, we get

a =  \frac{46}{17}  \\  b = 0
Hope it helps dear friend ☺️
Answered by TheLostMonk
1
here is it !
hope it helps !
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