Math, asked by battleking, 1 year ago

Find rational number a and b
2-√5/2+√5=a√5+b

Answers

Answered by DaIncredible
11
Hey friend,
Here is the answer you were looking for:
 \frac{2 -  \sqrt{5} }{2 +  \sqrt{5} }  = a \sqrt{5}  + b \\  \\  on \: rationalizing \: the \: denominator \: we \: get \\  \\  =  \frac{2 -  \sqrt{5} }{2 +  \sqrt{5} }  \times  \frac{2 -  \sqrt{5} }{2 -  \sqrt{5} }  \\  \\ using \: the \: identity \\   {(a - b)}^{2}  =  {a}^{2}  +  {b}^{2}  - 2ab \\ (a + b)(a - b) =  {a}^{2}  -  {b}^{2}  \\  \\  =  \frac{ {(2)}^{2}  +  { (\sqrt{5} )}^{2}  - 2(2)( \sqrt{5}) }{  {(2)}^{2} -  {( \sqrt{5} )}^{2} }  \\  \\  =  \frac{4 + 5 - 4 \sqrt{5} }{4 - 5}  \\  \\  =  \frac{9 - 4 \sqrt{5} }{ - 1}  \\  \\  =  - (9 - 4 \sqrt{5} ) \\  \\  =  - 9 + 4 \sqrt{5}  \\  \\   4 \sqrt{5}  - 9 \\  \\  = a \sqrt{5}  + b \\  \\ a = 4 \\  \\ b =  - 9

Hope this helps!!!

@Mahak24

Thanks...
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Answered by Anonymous
7
Hey, here is your answer....

a = 4, b = -9....

hope this helps you....

plzz mark it as brainliest..
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