Math, asked by vanesssa4575321, 7 months ago

solve the following question.

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Answered by Anonymous
3

Question:-

Find the value of a and b if

 \frac{7 + 3 \sqrt{5} }{3 +  \sqrt{5} }  -  \frac{7 - 3 \sqrt{5} }{3 -  \sqrt{5} }  = a + b \sqrt{5}

Solution:-

\frac{7 + 3 \sqrt{5} }{3 +  \sqrt{5} }  -  \frac{7 - 3 \sqrt{5} }{3 -  \sqrt{5} }

Take a lcm, we get

 \frac{(3 -  \sqrt{5} )(7 + 3 \sqrt{5}) - (3 +  \sqrt{5} )(7  - 3 \sqrt{5}  )}{(3 +  \sqrt{5} )(3 -  \sqrt{5} )}

Use this identity

=> (a-b)(c+d)=ac+ad-bc-bd

=>(a-b)(a+b)=(a²-b²)

By using this Identity,we get

 \frac{(21 + 9 \sqrt{5}  - 7 \sqrt{5} - 15)  - (21 - 9 \sqrt{5}  + 7 \sqrt{5} - 15 )}{9 - 5}

 \frac{21 + 9 \sqrt{5}  - 7 \sqrt{5} - 15 - 21 + 9 \sqrt{5}   - 7 \sqrt{5}  + 15}{4}

 \frac{2 \sqrt{5}  + 2  \sqrt{5}  }{4}

 \frac{4 \sqrt{5} }{4}

 \sqrt{5}

Now we can write as

0 + 1 \sqrt{5}

Answer:- a=0 and b=1

Answered by srujana57
1

Answer:

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Step-by-step explanation:

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