- #1

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Can someone help me solve this? I can't figure it out.

n^5+80=5n^4+16n

n^5+80=5n^4+16n

- Thread starter ymersion
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- #1

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Can someone help me solve this? I can't figure it out.

n^5+80=5n^4+16n

n^5+80=5n^4+16n

- #2

CompuChip

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Factorisation might work here. Especially if you can "guess" one root.

- #3

Borek

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Does n mean you are looking only for integer roots?

- #4

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n is just the variable, any rational answer will work. I've tried to factor but, I can't.

- #5

CompuChip

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Especially for homework assignments this tends to work, because the exercise is constructed such that most roots are integers near 0.

- #6

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I have the answer. I just don't know how to solve it. Answer is n=5,2,-2

- #7

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Move everything to one side and note that 80 = 5*16. Factor into a sum of two terms each involving a product of two terms. Then try to factor the resulting expression.

Last edited:

- #8

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- #9

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n^5-5n^4-16n+80=0

n^4(n-5)-16(n-5)=0

(n^4-16)(n-5)=0

n^4=16 and n-5=0

n=+/-2,5

- #10

Borek

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- #12

Borek

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There are many ways to skin that cat

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