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jobsafish
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I'm back with the maths questions! I have some equations to figure out, the first one is the number 75 can be written as 5x * y, where x and y are prime numbers. Find the value of x and the value of y. I suck at maths but I'm guessing x is 5 and y is 3? So 5*5=25*3=75? That's my best guess!
The next question is the number 96 can be written as 2m*n, where m and n are prime numbers. Find the value of m and the value of n. I'm totally lost, not got a clue. I think that m is a number which when multiplied by 2 makes a prime number that can then be multiplied by another prime number to equal 96?

Help me please!

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zaback21
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(Original post by jobsafish)
I'm back with the maths questions! I have some equations to figure out, the first one is the number 75 can be written as 5x * y, where x and y are prime numbers. Find the value of x and the value of y. I suck at maths but I'm guessing x is 5 and y is 3? So 5*5=25*3=75? That's my best guess!
The next question is the number 96 can be written as 2m*n, where m and n are prime numbers. Find the value of m and the value of n. I'm totally lost, not got a clue. I think that m is a number which when multiplied by 2 makes a prime number that can then be multiplied by another prime number to equal 96?

Help me please!

The 1st part is right.

For the 2nd question, it seems like you made a mistake in the question. 2m*n in no way can be 96 or even if its a typo on your behalf 2m^n can't be 96.
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arkanm
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(Original post by jobsafish)
I'm back with the maths questions! I have some equations to figure out, the first one is the number 75 can be written as 5x * y, where x and y are prime numbers. Find the value of x and the value of y. I suck at maths but I'm guessing x is 5 and y is 3? So 5*5=25*3=75? That's my best guess!
The next question is the number 96 can be written as 2m*n, where m and n are prime numbers. Find the value of m and the value of n. I'm totally lost, not got a clue. I think that m is a number which when multiplied by 2 makes a prime number that can then be multiplied by another prime number to equal 96?

Help me please!

I think they're trying to get you to find the prime factorizations of numbers and work from there.

They basically want you to show that 96 can't be written in the form 2mn where m,n are primes.

It's not that hard to prove that this can't be done. The reason is quite simple. 96 has 5 factors of 2 in its prime factorization (i.e. 96=2*2*2*2*2*3 - check this yourself!) Therefore we need 4 factors of 2 in the product mn. But if m,n are both primes this isn't possible.
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jobsafish
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I have been playing about with this all day, could it be 2^5*3=96??
As in could the 2m mean 2 to the power of m instead of 2*m?
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jobsafish
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(Original post by arkanm)
I think they're trying to get you to find the prime factorizations of numbers and work from there.

They basically want you to show that 96 can't be written in the form 2mn where m,n are primes.

It's not that hard to prove that this can't be done. The reason is quite simple. 96 has 5 factors of 2 in its prime factorization (i.e. 96=2*2*2*2*2*3 - check this yourself!) Therefore we need 4 factors of 2 in the product mn. But if m,n are both primes this isn't possible.
Could it mean 2 to the power of m *n?
So 2^5*3=96??
Its definitely wrote as 2m*n= 96 where m and n are both primes.
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arkanm
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They probably meant 2^5\times 3 then. Seems reasonable since 3 and 5 are primes, and also because 2\times m\times n=96 as I showed above.

Oh, here's an extension question I made for you, please try doing it yourself (I'll give hints if you want though):

Find the number of positive divisors of the number whose prime factorization is p^5\times q^2\times r^n in terms of n. (Note: here p,q and r are primes)
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arkanm
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E.g. 96=2^5*3 has 12 divisors: 1,2,3,4,6,8,16,32,12,24,48,96
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jobsafish
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Honestly, just looking at that actually hurts my brain.
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Livvylew
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the answer to your second question is 96 =32x3 96=2^5x3 m=5 n=3
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TSR Mustafa
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Lol are you that girl?
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