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by ajith » Tue Feb 09, 2010 9:34 am
billyr wrote:Thanks

(√ (9+√80) + √ (9-√80))^2

9+√80 + 9-√80 + 2*√ (9+√80)* √ (9-√80) [(a+b) ^2 = a^2+b^2 +2ab)
9+√80 + 9-√80 + 2*√ ((9+√80)* (9-√80))
9+9 + 2*√(9^2-√80^2) [(a+b)(a-b) = a^2-b^2]
9+9+2*√1
=20
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by thephoenix » Tue Feb 09, 2010 9:41 am
[v(9+v80)+v(9-v80)]^2=9+v80+9-v80+2(v(9+v80) * v(9-v80))=18+2[v(81-80)]=18+2=20
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by shashank.ism » Tue Feb 09, 2010 9:48 am
billyr wrote:Thanks
(√ (9+√80) + √ (9-√80))^2
= 9+√80 + 9-√80 + 2*√ (9+√80)* √ (9-√80) = 9+√80 + 9-√80 + 2*√ ((9+√80)* (9-√80))
=9+9 + 2*√(9^2-√80^2)=9+9+2*√1 =20 Ans
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