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How do you prove that?

2007-07-25 05:26:16 · 7 answers · asked by seerg e 1 in Science & Mathematics Mathematics

Yes I am talking about x as a natural number
Any x

2007-07-25 05:34:58 · update #1

7 answers

What you mean is that for any integer x, x^5 - x is divisible by 30, the subject being, not high-school algebra but number theory.
Every number is a multiple of 6 plus one of {0,1,2,3,4,5}.
[6x + {0,1,2,3,4,5}]^5 has what remainders when you divide by 6? For example 2^5 = 32 = 6*5 + 2. In other words
(6x + 2)^5 = 6z + 2, for some z. You will find that if you start with any number {0,1,2,3,4,5} you will have the same as remainders. So if you subtract them, X^5 - X will have remainders of zero. This means that X^5 - X is always divisible by six.
You can do the same thing with (5x + {0,1,2,3,4})^5 and you will find out the same thing; that all numbers of the form
x^5 - x are divisible by 5. Therefore it is also divisible by 30.

See Fermat's "little theorem" which applies here to the "divisible by five" part of the above argument.

2007-07-25 06:34:15 · answer #1 · answered by Anonymous · 0 0

x^5 - x = x(x^4 - 1). If x = 30 then the original statement is divisible by 30.

2007-07-25 12:31:21 · answer #2 · answered by John V 6 · 0 0

x = 2

x^5 - 2 = 32 - 2 = 30

2007-07-25 12:31:53 · answer #3 · answered by miggitymaggz 5 · 0 0

Anything can be divided by 30.

Are you asking if you get a whole number or a rational number or what?

2007-07-25 12:32:30 · answer #4 · answered by TychaBrahe 7 · 0 1

huh?

x^5-x=
x(x^4-1)

now if x was 2, then x(x^4-1) would equal 30, i'm not sure what you're looking for

2007-07-25 12:30:05 · answer #5 · answered by jnice160 2 · 0 1

Mathematical induction.

2007-07-25 12:29:38 · answer #6 · answered by ag_iitkgp 7 · 0 0

howwwwwwwwwwwwwwww

2007-07-25 12:32:28 · answer #7 · answered by Anonymous · 0 1

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