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Mathematics 16 Online
OpenStudy (lifeisadangerousgame):

plz help me solve this!

OpenStudy (lifeisadangerousgame):

\[\sqrt{27} - \sqrt{12} + \sqrt{8} X \sqrt{2}\]

OpenStudy (anonymous):

Decompose each number into its prime-power factors:\[\sqrt{3^3}-\sqrt{2^2\cdot3}+\sqrt{2^3}\cdot\sqrt{2}=3\sqrt{3}-2\sqrt{3}+2\sqrt{2}\cdot\sqrt{2}=\sqrt{3}+4\]

OpenStudy (lifeisadangerousgame):

ohh! Thanks!

OpenStudy (lifeisadangerousgame):

Can you help me with the rest?

OpenStudy (anonymous):

Just post them here and we will help you.

OpenStudy (lifeisadangerousgame):

Thanks! \[\sqrt[3]{x}^{5}\]

OpenStudy (anonymous):

That expression can't be reduced further:\[\sqrt[3]{x^5}=x^{5/3}\text{, gcd}(5,3)=1.\]

OpenStudy (lifeisadangerousgame):

Well, here's the possible answers:

OpenStudy (anonymous):

You can always rewrite it a thousand other ways, however, like\[\sqrt[3]{x^5}=x^2\sqrt[3]{x}\text{ and }x\sqrt[3]{x^3}.\]

OpenStudy (lifeisadangerousgame):

so wait, which one is it? I'm confused..

OpenStudy (anonymous):

The answer you're looking for is\[x^2\sqrt[3]{x}.\]

OpenStudy (lifeisadangerousgame):

ohh ok thank you!

OpenStudy (lifeisadangerousgame):

OpenStudy (lifeisadangerousgame):

How do I figure that one out?

OpenStudy (anonymous):

You have to use the Pythagorean theorem:\[a^2+b^2=c^2.\]However, since you have a square, we have that\[2a^2=c^2.\]Moreover, you are told that \(c=8\sqrt{2}\). So, \(c^2=128\). It follows that\[2a^2=128,\]\[a^2=64,\]\[a=8.\]Hence, the length of the side of the square is \(8\).

OpenStudy (lifeisadangerousgame):

ohhh ok :D Thank you!

OpenStudy (anonymous):

check this... \[\sqrt[3]{x^5}=x^2\sqrt[3]{x}\text{ and }x\sqrt[3]{x^3}\] is not right.

OpenStudy (anonymous):

@dpalnc is right: I overlooked the cube.

OpenStudy (lifeisadangerousgame):

oh so..it should be...

OpenStudy (lifeisadangerousgame):

The last question is: find a number between 3/4 and 3/5 and I chose 13/20, is that right?

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