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Mathematics 17 Online
OpenStudy (anonymous):

2.Simplify the given expression to rational exponent form, justify each step by identifying the properties of rational exponents used. All work must be shown.

OpenStudy (anonymous):

hero (hero):

\[\frac{1}{\sqrt[3]{x^{-6}}}\]

OpenStudy (anonymous):

@AravindG can you help explain how he got it

hero (hero):

I thought you wanted to understand how to simplify the expression.

OpenStudy (aravindg):

Its same as question?

hero (hero):

@deezgurls, do you want an explanation of how to simplify the expression?

OpenStudy (anonymous):

Yeah, I don't know how to simplify it D: Sorry for the hassle

hero (hero):

So first, understand the rule \[x^{-a} = \frac{1}{x^a}\] \(x^{-a}\) can be read as the "inverse of x to the a".

hero (hero):

In other words, the negative exponent means "inverse".

OpenStudy (anonymous):

Okay

hero (hero):

So the first property so apply is "inverse property of exponents", which after application we get: \[\dfrac{1}{\sqrt[3]{\dfrac{1}{x^6}}}\]

hero (hero):

From here, there are a few different rules we can use. First of all understand that \[\sqrt[3]{1^3} = 1\] \[\sqrt[6]{1^6} = 1\]

hero (hero):

Actually let's do this, rewrite the fraction as: \[\dfrac{1}{\dfrac{\sqrt[3]{1}}{\sqrt[3]{x^6}}}\] We can do that by way of the following rule: \[\sqrt[n]{\dfrac{a}{b}} = \dfrac{\sqrt[n]{a}}{\sqrt[n]{b}}\]

OpenStudy (anonymous):

okay, I wrote it down

hero (hero):

Next, we simplify the numerator of the inner fraction according to the rule above to get: \[\dfrac{1}{\dfrac{1}{\sqrt[3]{x^6}}}\]

OpenStudy (anonymous):

okay

hero (hero):

There's another rule we can utilize to attempt to simplify further: \[x^{ab} = (x^{a})^b\] In this case: \[x^6 = x^{(2)(3)} = (x^2)^3\]

OpenStudy (anonymous):

Alright

hero (hero):

So we can re-write the fraction as: \[\dfrac{1}{\dfrac{1}{\sqrt[3]{(x^2)^3}}}\]

hero (hero):

And we see yet another rule we can use. In general: \[\large\sqrt[n]{x^n} = x\]

hero (hero):

The root and exponent cancel if they have the same base.

hero (hero):

This is because \[\large\sqrt[n]{x^n} = x^{\frac{n}{n}} = x^1 = x\]

hero (hero):

So now we have just: \[\dfrac{1}{\dfrac{1}{x^2}}\] Which can be re-written as : \[1 \div \frac{1}{x^2}\] We can do this by way of the definition of division: \[\frac{a}{b} = a \div b\]

hero (hero):

Finally, we have the reciprocal rule, which utliizes the fact that division is merely the inverse of multiplication. In other words: \[a \div b = a \times \frac{1}{b}\] So we have: \[1 \div \frac{1}{x^2} = 1 \times x^2\]

hero (hero):

In other words, the final result is just \[x^2\]

OpenStudy (anonymous):

so the answer is x2?

OpenStudy (anonymous):

okay now i'm confused

hero (hero):

Basically, negative exponent doesn't mean the answer will be negative.

hero (hero):

Remember, negative exponent means "inverse"

hero (hero):

Also, remember, that we had to reduce the expression. And we used the rules of exponents and algebra to do so.

OpenStudy (anonymous):

Alright, thank you so much!

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