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Mathematics 15 Online
OpenStudy (heyitslizzy13):

someone please help me on simplifying expressions!

OpenStudy (dangerousjesse):

Do I need to make an example, or do you need help with a question?

OpenStudy (heyitslizzy13):

it's questions, but I did some trying to use the methods you showed me but I get stuck :/

OpenStudy (heyitslizzy13):

OpenStudy (dangerousjesse):

Okay

OpenStudy (dangerousjesse):

For your first one:

OpenStudy (mathmale):

Be aware that the topic here is "exponentiation" and that you're being asked to simplify expressions with exponents.

OpenStudy (heyitslizzy13):

yes, I'm sorry.

OpenStudy (mathmale):

For Problem #59: Imagine you had (a/b)^(-1). How would you evaluate that?

OpenStudy (mathmale):

In nicer format, that'd be \[(\frac{ a }{ b })^{-1}\]

OpenStudy (heyitslizzy13):

do the reciprocal since it has a negative exponent? :/

OpenStudy (mathmale):

Yes. Go ahead: try it.

OpenStudy (heyitslizzy13):

1/ (a/b) ?

OpenStudy (mathmale):

That's correct, but it'd be much easier simply to write b/a, don't you think?

OpenStudy (mathmale):

\[(a/b)^{-1}=b/a\]

OpenStudy (heyitslizzy13):

may I ask why b/a is easier than a/b because I'm kind of confused :/ ?

OpenStudy (anonymous):

(2x^3 y^4)^5 2^5x^15 y^20 (32x^15 y^20) \[32x^15 y^20\]

OpenStudy (anonymous):

thats question 68 and the last one is supposed to be 32^15 y^20

OpenStudy (mathmale):

What I actually said was that your (correct)\[\frac{ 1 }{ a/b }\]is more simply expressed as b/a. I inverted (a/b) to obtain (b/a).

OpenStudy (dangerousjesse):

Simplify the following: \[x^2/(1/(x^3 y^2)) \]\[ x^2/(1/(x^3 y^2)) \]as a single fraction. Multiply the numerator of \[ \frac{x^2}{\frac{1}}{\frac{x^3 y^2}}\] by the reciprocal of the denominator. \[ \frac{x^2}{\frac{1}{x^3 y^2}} = x^2 x^3 y^2: \]\[x^2 x^3 y^2 \]Combine products of like terms. \[x^2 x^3 y^2 = x^{2+3} y^2:\]\[x^{2+3} y^2\]Evaluate 2+3. \[2+3 = 5: \]God, it's so hard to type fractions on fractions, sorry -.-

OpenStudy (dangerousjesse):

Oops that was a waste of time.

OpenStudy (mathmale):

Too many helpers here, I'm afraid. Which one of us is going to bow out?

OpenStudy (dangerousjesse):

That'll be me, I helped her enough earlier :P

OpenStudy (mathmale):

Sweet of you. Apparently you're not as dangerous as your name implies.

OpenStudy (heyitslizzy13):

dominiquebee72 where's the 32 from..?

OpenStudy (heyitslizzy13):

thank you all for helping, I appreciate it, if I haven't replied it's because i'm going over it :)

OpenStudy (mathmale):

Here you see the danger in providing answers without explanations and without involving the person asking the question. Please, @dominiquebee72, help @heyitslizzy13 to find her own answers by providing her with guidance along the way.

OpenStudy (heyitslizzy13):

thanks @mathmale I don't even know which problem to look at I'm so confused .-.

OpenStudy (mathmale):

@heyitslizzy13 : Please look at Problem #59:\[(\frac{ x^2 }{ x ^{-3}y ^{-2} })^{-1}\]and then apply what I was demonstrating earlier. In other words, simply flip the quantity within the parentheses.

OpenStudy (heyitslizzy13):

so x^3 y^2 / x^2 ?

OpenStudy (heyitslizzy13):

@DangerousJesse thanks a lot for your help!! :)

OpenStudy (mathmale):

If we invert the quantity inside parentheses, we'd get \[\frac{ x ^{-3}y ^{-2} }{ x^2 }\]... note that the exponent is now gone.

OpenStudy (mathmale):

What's the last thing you'd do to simplify this? Remember, we don't want negative exponents.

OpenStudy (heyitslizzy13):

wait what happened to the exponent on the outisde..? I thought the exponents would then be positive since we did the reciprocal ?

OpenStudy (mathmale):

There was a negative 1 exponent. We got rid of that simply by inverting / flipping the quantity within the parentheses.

OpenStudy (mathmale):

Or, as you say, we found the reciprocal of the original quantity within parentheses.

OpenStudy (heyitslizzy13):

oh sorry, I thought you had to apply the -1 exponent to the numbers inside the parentheses

OpenStudy (mathmale):

You certainly can do EITHER that OR flip the original quantity within parentheses. I chose to do the latter.

OpenStudy (mathmale):

So, going back to \[\frac{ x ^{-3}y ^{-2} }{ x^2 }\]how are you going to eliminate those negative exponents?

OpenStudy (heyitslizzy13):

reciprocal again?

OpenStudy (mathmale):

That would work. What i'd suggest, however, is that you recognize that that \[x ^{-3}\]in the numerator becomes x^3 in the denominator. Can you agree with that? if so, what is (x^3)(x^2)?

OpenStudy (heyitslizzy13):

x^5?

OpenStudy (mathmale):

Yes. So your newest and last denominator is x^5. What happens to that \[y ^{-2}\]in the numerator?

OpenStudy (mathmale):

Hint: re-write \[y ^{-2}\] with positive exponent.

OpenStudy (heyitslizzy13):

y^2 / x^5 ?

OpenStudy (heyitslizzy13):

i'm still not sure how I even got there .-.

OpenStudy (mathmale):

that \[y ^{-2}\] becomes \[\frac{ 1 }{ y^2 }\]so,

OpenStudy (mathmale):

\[\frac{ y ^{-2} }{ x^2 }\] becomes what?

OpenStudy (mathmale):

sorry, I meant\[\frac{ y ^{-2} }{ x^5 }\]

OpenStudy (heyitslizzy13):

x^5 / y^2 ?

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