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Mathematics 8 Online
OpenStudy (beccab003):

simplifying radicals.

OpenStudy (beccab003):

@DanJS

OpenStudy (danjs):

ok

OpenStudy (beccab003):

Here is the question: -\[\sqrt[4]{96x ^{8}y ^{4}}\]

OpenStudy (danjs):

k, write out each step

OpenStudy (beccab003):

sorry, there is a negative before the equation

OpenStudy (beccab003):

Okay firstly, you times 8*1/8

OpenStudy (beccab003):

and 4*1/4

OpenStudy (beccab003):

right?

OpenStudy (danjs):

this one is a bit easier than the last

OpenStudy (beccab003):

so it's: \[-\sqrt[4]{96xy}\]

OpenStudy (danjs):

\[(-1) * \sqrt[4]{96 * x^8*y^4}\] first take down the radical on teh x and y and make them to the 1/4th power

OpenStudy (beccab003):

Okay so it's 1/8*4 and 4*1/4

OpenStudy (danjs):

\[(-1) * \sqrt[4]{96 * x^8*y^4} = (-1) *\sqrt[4]{96}*[x^8]^{1/4} * [y^4]^{1/4}\]

OpenStudy (danjs):

[x^8]^(1/4) = x^(8/4) = x^2

OpenStudy (danjs):

(y^4)^(1/4) = y^(4/4) = y

OpenStudy (beccab003):

OH! I get it!

OpenStudy (danjs):

: )

OpenStudy (beccab003):

so now it looks like: \[-1\sqrt[4]{96x ^{2}y}\]

OpenStudy (beccab003):

except you move 'em over...the x^2 and y

OpenStudy (danjs):

right, they are outside the root now

OpenStudy (beccab003):

okay so, before I move 'em over I'll find the perfect square of 96

OpenStudy (danjs):

\[-1*\sqrt[4]{96}*x^2*y\]

OpenStudy (danjs):

for the 4th root of 96, start breaking down 92 into smaller factors 96 = 2*48 = 2*2*24 = 2*2*2*12 = 2*2*2*2*6

OpenStudy (danjs):

there you see you have 4 2's 96 = 2^4 * 6

OpenStudy (beccab003):

So to find the perfect square of 96 this is what I did: 96/2 48/4 12/6 =2

OpenStudy (danjs):

It is the 4th root, not square. I just kept dividing by 2, and pulling 2's out of 96 96 = 2 * 2 * 2 * 2 * 6

OpenStudy (danjs):

\[\sqrt[4]{96} = \sqrt[4]{2^4*6} = 2*\sqrt[4]{6}\]

OpenStudy (danjs):

[2^4]^(1/4) = 2^(4/4) = 2

OpenStudy (beccab003):

oh! just keep dividing by two's! So throughout these problems you are continually using that 4 on the root?

OpenStudy (danjs):

right, the 4th root of (96*x^8*y^4) is the same as (96*x^8*y^4)^(1/4)

OpenStudy (beccab003):

That makes so much more sense! I had no idea what that was for!

OpenStudy (danjs):

right, so what is the final answer

OpenStudy (beccab003):

So final answer: \[-2x ^{2}y \sqrt[4]{6}\]

OpenStudy (beccab003):

in my math class they put the x and y variables on the other side.

OpenStudy (danjs):

in front of the root ?

OpenStudy (beccab003):

yup! I don't know...it's weird that way but that's what they say is right.

OpenStudy (danjs):

It really doesn't matter, but usually the numbers are in front of the variables

OpenStudy (danjs):

If you want to do another, i have time for one more

OpenStudy (beccab003):

YOU HAVE BEEN SO EPICLY AMAZING! I do have one more that I would like to do because it does have a number by the square root like this problem had the number 4.

OpenStudy (beccab003):

*it doesn't

OpenStudy (beccab003):

should I open it in a new question and then tag you and close it?

OpenStudy (danjs):

yeah

OpenStudy (beccab003):

k

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