Could somebody please help me study for a pre-algebra test? I have some questions.

- anonymous

Could somebody please help me study for a pre-algebra test? I have some questions.

- Stacey Warren - Expert brainly.com

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- katieb

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- slaaibak

We will be here to answer your questions :)

- anonymous

Okay thanks! I really appreciate it.

- anonymous

Okay. sooo, this is really broad, but I don't understand negative exponents.... At all.

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## More answers

- Akshay_Budhkar

So you got some specific questions or do you want me or us to explain you negative exponents from scratch?

- anonymous

Ummmmmmm. Why does a negative exponent make a fraction? I don't understand the basic concept.

- slaaibak

Negative exponents simply means this:
\[a^{-x} = {1 \over a^x}\]

- Akshay_Budhkar

yea slaaibak got it

- anonymous

Yes but why are they defined that way?

- Akshay_Budhkar

it is simple

- Akshay_Budhkar

do you know
\[a^x \times a^y= a^{x+y}\]

- anonymous

No.

- Akshay_Budhkar

now say we want
\[a^x \times a^y = 1\]

- anonymous

Well yeah I do sorry.

- anonymous

Okay.

- anonymous

You'd made one negative!!! AHHH I GET IT!

- Akshay_Budhkar

so when we solve that we get
\[a^{x+y}= 1 = a^0\]

- Akshay_Budhkar

thats good! You get it :D

- anonymous

Teehee! Wow that just clicked. My math teacher didn't explain it that way.......

- Akshay_Budhkar

its my pleasure helping you click it :D

- anonymous

So another thing, how do you deal with #s with exponents in a fraction?

- slaaibak

Give an example please?

- anonymous

Ummmm. How do you make fractions with this equation thing?

- slaaibak

type over

- anonymous

...

- Akshay_Budhkar

3 over 4
\[3 \over 4\]

- slaaibak

Use this code: {1 over 2}
would be
\[{1 \over 2}\]

- anonymous

... Um can I just say it?

- Akshay_Budhkar

yea what is your doubt? i do not comprehend it

- slaaibak

yeah sure

- anonymous

Okay so if you had y^-5 times 2^3 over y^4 times x^2.

- anonymous

Or something to that effect.

- Akshay_Budhkar

\[ y^-5 \times 2^3 \over y^4 \times x^2.\]

- slaaibak

\[{ y^{-5} * 2^3 \over y^4 * x^2}\]

- Akshay_Budhkar

is that your query?

- anonymous

Lol yeah.

- slaaibak

You're faster than me xD

- Akshay_Budhkar

i am not lol

- anonymous

=.=

- anonymous

?

- slaaibak

If there's multiplication, you can take y^-5 and but it below the line,
\[y^{-5} = {1 \over y^5}\]
You can immediately write 2^3 as 8.
So now you have:
\[{1 \over y^5} * {8 \over x^2 * y^4}\]

- slaaibak

put*, not but

- slaaibak

Then, you can multiply similar variables with eachother and add the powers.
it becomes:
\[8 \over y^9 * x^2\]

- anonymous

What are you talking about?

- Akshay_Budhkar

about the question you asked

- slaaibak

I made a spelling mistake in my post.

- anonymous

Yeah but how did you get y^9?

- anonymous

I know you have to add... Or subtract the exponents or something.

- slaaibak

\[y^4 * y^5 = y^{5 + 4}\]

- anonymous

OH okay.

- Akshay_Budhkar

the main aim of such questions is to convert your negative exponents into positive by taking its reciprocal

- anonymous

Um one more thing. How would you get {1 over 9} % of 90. Or something like that.

- anonymous

Aw shoot. I messed up the thing.

- anonymous

\[{1 \over 9}\]

- Akshay_Budhkar

percent is always divided by 100

- anonymous

Yes.

- Akshay_Budhkar

so 1/9 percent is \[(1/9 ) \over 100 = 1\over900\]

- Akshay_Budhkar

1/900

- anonymous

Sure...

- Akshay_Budhkar

of 90 is 1/900 of 90.. of implies multiplication

- Akshay_Budhkar

so it is
1/900 times 90 = 90/900 = 1/10

- anonymous

Yes yes I get it.

- anonymous

That makes sense! Okay that's all! And I have to go. Thank you so much. ^.^

- Akshay_Budhkar

it is my pleasure

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