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hana88
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if x is an integer divisible by 3, then x^2 is divisible by 3. is this true or false? is the converse true or false?
 2 years ago
 2 years ago
hana88 Group Title
if x is an integer divisible by 3, then x^2 is divisible by 3. is this true or false? is the converse true or false?
 2 years ago
 2 years ago

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hana88 Group TitleBest ResponseYou've already chosen the best response.0
can any one help?
 2 years ago

just.chris Group TitleBest ResponseYou've already chosen the best response.1
x = N x 3, represents the divisible by 3 integer. x^2 then equals N^2 x 3^2 which having the factors of 3 is therefore divisible by 3. Is this useful?
 2 years ago

hana88 Group TitleBest ResponseYou've already chosen the best response.0
yes thank you
 2 years ago

hana88 Group TitleBest ResponseYou've already chosen the best response.0
what about the converse?
 2 years ago

lopus Group TitleBest ResponseYou've already chosen the best response.0
X=2*3 6/3=2 \[x^{2}=36\] 36/3=12
 2 years ago

hana88 Group TitleBest ResponseYou've already chosen the best response.0
that only gives me evidence
 2 years ago

just.chris Group TitleBest ResponseYou've already chosen the best response.1
I haven't done this stuff in awhile. Do you mean if and integer, x, is divisible by 2 then x^3 is also divisible by 2?
 2 years ago

hana88 Group TitleBest ResponseYou've already chosen the best response.0
no if x^2 is divisive by 3, then x is divisible by 3
 2 years ago

just.chris Group TitleBest ResponseYou've already chosen the best response.1
OK. I am winging it here In order for x^2 to be divisible by a prime, which cannot be further factored then it must also be a factor of x. Is this useful?
 2 years ago

lopus Group TitleBest ResponseYou've already chosen the best response.0
x=n*3 n=1,2,3,4,5,6,7,8............... x^2=3,36,81,144....... divide
 2 years ago

hana88 Group TitleBest ResponseYou've already chosen the best response.0
@lopus x is 3,6,9,12,18...
 2 years ago

just.chris Group TitleBest ResponseYou've already chosen the best response.1
x = 3,6,9,... is correct valus for x but does that indicate that if x^2 is divisible by 3 then so is x? I am asking because I don't know. A question about the question.
 2 years ago

lopus Group TitleBest ResponseYou've already chosen the best response.0
yes, you just divide and see for yourself demostration x=N*3 (N*3)^2 =n^2 * 3^3
 2 years ago

lopus Group TitleBest ResponseYou've already chosen the best response.0
excuse me 3^2
 2 years ago

just.chris Group TitleBest ResponseYou've already chosen the best response.1
So you don't really need the series you just need if x^2 is divisible by 3 then x is because 3 cannot be further factored. And the equations you provided apply in bothe directions. unlike say if x^2 is divisible by 4 then x is not necessarily divisible by for because 4 can be further factored, i.e., 2^2 = 4 is divisible by 4 but x, being 2, is not. Yes?
 2 years ago

Mertsj Group TitleBest ResponseYou've already chosen the best response.1
If x^2 is divisible by 3 it can be written in the form 3a where a is an integer. So x^2=3a and x = sqrt3(sqrt a) so the converse is not true.
 2 years ago

helder_edwin Group TitleBest ResponseYou've already chosen the best response.0
3 is a prime number. u should pay attention to that!!!
 2 years ago

hana88 Group TitleBest ResponseYou've already chosen the best response.0
um @helder you make no sense
 2 years ago

hana88 Group TitleBest ResponseYou've already chosen the best response.0
@Mertsj thanks thats the best answer because it was easy to understand
 2 years ago

helder_edwin Group TitleBest ResponseYou've already chosen the best response.0
if \(3\mid x^2\) then \(3\mid x\) because 3 is prime.
 2 years ago

Mertsj Group TitleBest ResponseYou've already chosen the best response.1
That is not true helder. 315 but 3 does not divide sqrt15
 2 years ago

Mertsj Group TitleBest ResponseYou've already chosen the best response.1
So if x^2 = 15, 3 is a factor of x^2 but not a factor of x
 2 years ago

helder_edwin Group TitleBest ResponseYou've already chosen the best response.0
but 15 is not a perfect square!
 2 years ago

Mertsj Group TitleBest ResponseYou've already chosen the best response.1
The converse is: If x^2 is divisible by 3 then x is an integer divisible by 3. So we see that x^2 does not have to be a perfect square. It only has to be divisible by 3.
 2 years ago

helder_edwin Group TitleBest ResponseYou've already chosen the best response.0
so why it is x^2 if it is not a perfect square?
 2 years ago

Mertsj Group TitleBest ResponseYou've already chosen the best response.1
x^2 could be 15 or 18 or 21 or 24 or 27 or 12 .
 2 years ago

helder_edwin Group TitleBest ResponseYou've already chosen the best response.0
nerver mind.
 2 years ago

just.chris Group TitleBest ResponseYou've already chosen the best response.1
If x^2 does not have to be a perfect square then the converse is not true. However, if x^2 is perfect and divisible by 3 then is the converse true? And would that be the case for any prime? Since primes cannot be factored into smaller integers then I think in order for the square to be factorable by the prime then you must have the prime^2 in order to have the prime as a factor of x^2.
 2 years ago
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