<PRE><B>Question 695216</B>
(4rad5 + 5)^2 
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= (4sqrt(5) + 5)(4sqrt(5) + 5)
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Use FOIL:
F: 4sqrt(5)*4sqrt(5) = 16*5 = 80
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O: 4sqrt(5)*5 = 20sqrt(5)
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I: 5*4sqrt(5) = 20sqrt(5)
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L: 5*5 = 25
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Combine those products to get: 105 + 40sqrt(5)
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Cheers,
Stan H.
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