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Mathematics 13 Online
OpenStudy (anonymous):

How would i simplify these radicals?

OpenStudy (anonymous):

\[\sqrt[3]{16} + \sqrt[3]{54}\]

OpenStudy (anonymous):

\[2(\sqrt[3]{40}) - \sqrt[3]{5}\]

OpenStudy (anonymous):

\[5(\sqrt[3]{48}) - 2(\sqrt[3]{162})\]

OpenStudy (turingtest):

by factoring the numbers under the radicals

OpenStudy (lgbasallote):

what are the indeces? 2? sorry..kinda hard to read...

OpenStudy (turingtest):

at least that is a good first step

OpenStudy (turingtest):

they are 3's

OpenStudy (turingtest):

you can right-click to make it larger

OpenStudy (turingtest):

so nicole, what is the prime factorization of 16 ?

OpenStudy (anonymous):

2,2,2,2 ? so \[2^{4}\]

OpenStudy (turingtest):

right now we want the cubed root of that so we want to break this up so we can recognize the powers of 3 so note that this is\[\sqrt[3]{2^3\cdot2}=2\sqrt[3]2\]make sense?

OpenStudy (turingtest):

\[\sqrt[3]{16}=\sqrt[3]{2^4}=\sqrt[3]{2^3\cdot2}=\sqrt[3]{2^3}\cdot\sqrt[3]2=2\sqrt[3]2\]

OpenStudy (anonymous):

how does \[\sqrt[3]{2^{3}\times 2} = \sqrt[3]{2^{3}}\] ? :S

OpenStudy (turingtest):

it doesn't, read above more closely

OpenStudy (turingtest):

\[\sqrt[3]{2^{3}\cdot 2} = \sqrt[3]{2^{3}}\cdot\sqrt[3]2\]

OpenStudy (anonymous):

i meant \[\sqrt[3]{2^{3}} \times \sqrt[3]{2}\]

OpenStudy (turingtest):

because powers (and therefor roots) are distributive over multiplication test it...

OpenStudy (turingtest):

\[\sqrt{36}=\sqrt{4\cdot9}=\sqrt4\cdot\sqrt9=2\cdot3=6\]it's just true :)

OpenStudy (anonymous):

oh okay, now i get it :) yeah that does make sense

OpenStudy (turingtest):

so you now see how\[\sqrt[3]{16}=2\sqrt[3]2\]? if so try the next one\[\sqrt[3]{54}\]

OpenStudy (anonymous):

\[\sqrt[3]{54} = \sqrt[3]{2 \times 3^{3}} = \sqrt[3]{2} \times \sqrt[3]{3} \] ? :S

OpenStudy (anonymous):

\[= 3\sqrt[3]{2} \]

OpenStudy (turingtest):

yes, nice :) now what is the final answer?

OpenStudy (anonymous):

the final answer is \[5\sqrt[3]{2}\]

OpenStudy (turingtest):

exactly :) good job

OpenStudy (anonymous):

thanks ! :) i'll get back to yo on the other questions once i finish them.

OpenStudy (turingtest):

You're welcome :)

OpenStudy (anonymous):

\[2(\sqrt[3]{40}) - \sqrt[3]{5} \]\[= 2(\sqrt[3]{2^{3}\times 5}) - \sqrt[3]{5} \]\[= 2(2\sqrt[3]{5}) - \sqrt[3]{5} \]\[= 4\sqrt[3]{5} - \sqrt[3]{5} \]\[= 3\sqrt[3]{5} \] \[5(\sqrt[3]{48}) - 2(\sqrt[3]{162}) \]\[= 5(\sqrt[3]{2^{4} \times 3}) - 2(\sqrt[3]{3^{4} \times 2}) \]\[= 5(\sqrt[3]{2^{4}} \times \sqrt[3]{3}) - 2(\sqrt[3]{3^{4}} \times \sqrt[3]{2}) \]\[= 5(2\sqrt[3]{2} \times \sqrt[3]{3}) - 2(3\sqrt[3]{3} \times \sqrt[3]{2}) \]\[= 5(2\sqrt[3]{6}) - 2(3\sqrt[3]{6}) \]\[= 10\sqrt[3]{6} - 6\sqrt[3]{6} \]\[= 4\sqrt[3]{6}\]

OpenStudy (anonymous):

wow that took a while for me to get on here. lol

OpenStudy (anonymous):

did i take the right steps? :)

OpenStudy (turingtest):

that looks perfect :D excellent job :)

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