Math, asked by harshpreet7, 1 year ago

3+√7/3-√7-3-√7/3+√7 please answer class 8 question

Answers

Answered by 1esha57
13
Hey friend here your answer.....
____________________________________3-3+√7/3-√7/3-√7+√7
=0. (ans)

harshpreet7: sorry but the answer at the back of my book is six aqare root 7
Answered by DaIncredible
5
Hey friend,
Here is the answer you were looking for:
 \frac{3 +  \sqrt{7} }{3 -  \sqrt{7} }  -  \frac{3 -  \sqrt{7} }{3 +  \sqrt{7} }  \\  \\ on \: rationalizing \: the \: denominator \: we \: get \\  \\  =  \frac{3 +  \sqrt{7} }{3 -  \sqrt{7} }  \times  \frac{3 +  \sqrt{7} }{3 +  \sqrt{7} }  -  \frac{3 -  \sqrt{7} }{3  +   \sqrt{7} }  \times  \frac{3 -  \sqrt{7} }{3 -  \sqrt{7} }  \\  \\  using \: the \: identities \\  \\  {(a + b)}^{2}  =  {a}^{2}  +  {b}^{2}  + 2ab \\  {(a  - b)}^{2}  =  {a}^{2}  +  {b}^{2}  - 2ab \\  (a + b)(a - b)  =  {a}^{2}  -  {b}^{2}  \\  \\  =  \frac{ {(3)}^{2} +  {( \sqrt{7}) }^{2}   + 2 \times 3 \times  \sqrt{7} }{ {(3)}^{2}    -    {( \sqrt{7} })^{2} }  -  \frac{ {(3)}^{2}   +    {( \sqrt{7}) }^{2}   - 3 \times 3 \times  \sqrt{7} }{ {(3)}^{2}  -  {( \sqrt{7} )}^{2} }  \\  \\  =  \frac{9  + 7 + 6 \sqrt{7} }{9 - 7}  -  \frac{9 + 7 - 6 \sqrt{7} }{9 - 7}  \\  \\  =  \frac{9 + 7 + 6 \sqrt{7} - 9 - 7 + 6 \sqrt{7}  }{2}  \\  \\  =  \frac{6 \sqrt{7}  + 6 \sqrt{7} }{2}  \\  \\  =  \frac{12 \sqrt{7} }{2}  \\  \\  = 6 \sqrt{7}


Hope this helps!!!

@Mahak24

Thanks...
☺☺

harshpreet7: thankyou so much
DaIncredible: my pleasure... Glad to help... Thnx for brainliest
harshpreet7: yours welcome
DaIncredible: :)
harshpreet7: its a pleasure
DaIncredible: ^_^
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