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Mathematics 6 Online
OpenStudy (beccab003):

radical question.

OpenStudy (beccab003):

@DanJS

OpenStudy (beccab003):

\[\sqrt[3]{81x^6y^9}\]

OpenStudy (beccab003):

I can show you the process that I went through if you want.

OpenStudy (danjs):

that one is pretty straight forward

OpenStudy (beccab003):

\[\sqrt[3]{81x^6y^9}=\sqrt[3]{81^\frac{ 1 }{ 3 }x^\frac{ 6 }{ 3 }y^\frac{ 9 }{ 3 }}\]

OpenStudy (danjs):

you did it right, and divided the powers by 3, but you left the root on it

OpenStudy (beccab003):

\[\sqrt[3]{27x^2y^3}\]

OpenStudy (beccab003):

how did you get 81 to become three?

OpenStudy (danjs):

\[\sqrt[3]{27x^2y^3} = \sqrt[3]{3^3} * \sqrt[3]{x^2}*\sqrt[3]{y^3} = 3*x^{2/3}*y\]

OpenStudy (danjs):

sorry the first one i messed it up

OpenStudy (danjs):

\[\sqrt[3]{81} = \sqrt[3]{3*3*3*3} = \sqrt[3]{3^3*3} = 3*\sqrt[3]{3}\]

OpenStudy (beccab003):

okay. I saw it like this: \[\sqrt[3]{81}=\sqrt[3]{27}=3\]

OpenStudy (danjs):

nah, i messed it up, the cubed root of 81 is 3 times the cubed root of 3

OpenStudy (beccab003):

Okay. So we now have: \[3\sqrt{x^2y^3}\]

OpenStudy (beccab003):

sorry i meant: \[3\sqrt[3]{x^2y^3}\]

OpenStudy (danjs):

lets start over here... \[\sqrt[3]{81x^6y^9} = \sqrt[3]{81}*\sqrt[3]{x^6}*\sqrt[3]{y^9}\]

OpenStudy (danjs):

\[\sqrt[3]{81} = \sqrt[3]{3^3*3} = 3\sqrt[3]{3}\]

OpenStudy (danjs):

\[\sqrt[3]{x^6} = x^2~~~and~~~~\sqrt[3]{y^9} = y^3\]

OpenStudy (danjs):

\[\sqrt[3]{81x^6y^9} = 3*\sqrt[3]{3}*x^2*y^3\]

OpenStudy (beccab003):

okay. So I didn't put the root 3. Sorry I see. So final answer: (written how my class shows it) \[3x^2y^3\sqrt[3]{3}\]

OpenStudy (danjs):

ok, yeah that is the same as the post above, they just put the radical at the end

OpenStudy (danjs):

either way is right

OpenStudy (beccab003):

yeah that's what i meant by the way my class does it. they always have the y and x variables on the left side.

OpenStudy (danjs):

they dont take points off if you put them in a different order do they? it is all multiplication

OpenStudy (danjs):

i am just used to writing the variables after numbers, it doesnt really matter though

OpenStudy (beccab003):

No they don't. I was just told that on the final, which is multiple choice, they will have it written like that.

OpenStudy (danjs):

ahh, ok if you want to do another i have some time

OpenStudy (beccab003):

sweet! I'll start a new thread.

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