Question 137047
f(n) = 7n^5+7n^4-3n^2-6n-3
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= 7n^4(n+1) -3(n^2+2n+1)

= 7n^4(n+1) -3(n+1)^2

= (n+1)[7n^4 -3(n+1)]

= (n+1)[7n^4-3n-3]
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Comment: 7n^4 -3n -3 is not factorable in the Real Number system.
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Cheers,
Stan H.