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Mathematics 13 Online
OpenStudy (brinazarski):

Can someone please help me solve this problem? http://i158.photobucket.com/albums/t120/brinazarski2/q_zps284189ee.png

OpenStudy (mertsj):

\[7x^5=11y^{13}\] \[y ^{13}=\frac{7}{11}x^5\] So one of the factors of x has to be 11

OpenStudy (brinazarski):

Why 11?

OpenStudy (brinazarski):

And shouldn't x^5 be divided by 11 as well?

OpenStudy (mertsj):

I divided both sides of the equation by 11

OpenStudy (brinazarski):

Yes... but how does that make one of the factors 11?

OpenStudy (mertsj):

the problem says that y and x are both integers. That means that the powers of x and y are also integers and the multiples of x and y are integers. So y^13 is an integer. but y^13 = 7/11 x^5. So if y^13 is going to be an integer, 11 must divide into x^5 since it will not divide into 7

OpenStudy (brinazarski):

Okay... but since we're looking for x, shouldn't it be the other way around?

OpenStudy (mertsj):

I thought you wanted the factors of x. sorry.

OpenStudy (brinazarski):

I do. I'm bad at math, I have no idea what I'm doing lol

OpenStudy (brinazarski):

That's why I need help

OpenStudy (brinazarski):

Tushara, tbansal, are you two still here and do you know how to do this? >.<

OpenStudy (anonymous):

hey... m still here, im not quite sure how to do it, ill let u know if i figure it out

OpenStudy (brinazarski):

okay, thank you!!! I'm so lost ._.

OpenStudy (mertsj):

D 33

OpenStudy (brinazarski):

How did you get that answer?

OpenStudy (mertsj):

We have seen that 11 has to be one of the factors. Similarly, 7 has to be one of the factors. So 7 (11^?)(7^?)=11(11^?)(7^?) Put the smallest exponents on those necessary to make them equal. You will see that those numbers are 13 and 12. So 13 + 12 + 7 + 11 = 33

OpenStudy (brinazarski):

Dang... how'd you come up with 12 and 13? Though I see it works, did you just plug it in or was there some way you found them? And thank you!

OpenStudy (mertsj):

I found the smallest numbers that would make the exponents on both sides the same.

OpenStudy (mertsj):

You had to start with 13 because one side was raised to the 13th power. Since there was already a 7, the factor 7 only had to be raised to the 12th power.

OpenStudy (brinazarski):

Ah, that makes sense... okay, thank you so much! :)

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