MetalPen
Could somebody please help me study for a pre-algebra test? I have some questions.
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slaaibak
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We will be here to answer your questions :)
MetalPen
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Okay thanks! I really appreciate it.
MetalPen
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Okay. sooo, this is really broad, but I don't understand negative exponents.... At all.
Akshay_Budhkar
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So you got some specific questions or do you want me or us to explain you negative exponents from scratch?
MetalPen
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Ummmmmmm. Why does a negative exponent make a fraction? I don't understand the basic concept.
slaaibak
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Negative exponents simply means this:
\[a^{-x} = {1 \over a^x}\]
Akshay_Budhkar
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yea slaaibak got it
MetalPen
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Yes but why are they defined that way?
Akshay_Budhkar
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it is simple
Akshay_Budhkar
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do you know
\[a^x \times a^y= a^{x+y}\]
MetalPen
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No.
Akshay_Budhkar
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now say we want
\[a^x \times a^y = 1\]
MetalPen
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Well yeah I do sorry.
MetalPen
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Okay.
MetalPen
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You'd made one negative!!! AHHH I GET IT!
Akshay_Budhkar
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so when we solve that we get
\[a^{x+y}= 1 = a^0\]
Akshay_Budhkar
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thats good! You get it :D
MetalPen
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Teehee! Wow that just clicked. My math teacher didn't explain it that way.......
Akshay_Budhkar
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its my pleasure helping you click it :D
MetalPen
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So another thing, how do you deal with #s with exponents in a fraction?
slaaibak
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Give an example please?
MetalPen
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Ummmm. How do you make fractions with this equation thing?
slaaibak
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type over
MetalPen
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...
Akshay_Budhkar
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3 over 4
\[3 \over 4\]
slaaibak
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Use this code: {1 over 2}
would be
\[{1 \over 2}\]
MetalPen
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... Um can I just say it?
Akshay_Budhkar
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yea what is your doubt? i do not comprehend it
slaaibak
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yeah sure
MetalPen
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Okay so if you had y^-5 times 2^3 over y^4 times x^2.
MetalPen
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Or something to that effect.
Akshay_Budhkar
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\[ y^-5 \times 2^3 \over y^4 \times x^2.\]
slaaibak
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\[{ y^{-5} * 2^3 \over y^4 * x^2}\]
Akshay_Budhkar
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is that your query?
MetalPen
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Lol yeah.
slaaibak
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You're faster than me xD
Akshay_Budhkar
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i am not lol
MetalPen
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=.=
MetalPen
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?
slaaibak
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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
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put*, not but
slaaibak
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Then, you can multiply similar variables with eachother and add the powers.
it becomes:
\[8 \over y^9 * x^2\]
MetalPen
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What are you talking about?
Akshay_Budhkar
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about the question you asked
slaaibak
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I made a spelling mistake in my post.
MetalPen
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Yeah but how did you get y^9?
MetalPen
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I know you have to add... Or subtract the exponents or something.
slaaibak
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\[y^4 * y^5 = y^{5 + 4}\]
MetalPen
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OH okay.
Akshay_Budhkar
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the main aim of such questions is to convert your negative exponents into positive by taking its reciprocal
MetalPen
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Um one more thing. How would you get {1 over 9} % of 90. Or something like that.
MetalPen
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Aw shoot. I messed up the thing.
MetalPen
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\[{1 \over 9}\]
Akshay_Budhkar
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percent is always divided by 100
MetalPen
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Yes.
Akshay_Budhkar
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so 1/9 percent is \[(1/9 ) \over 100 = 1\over900\]
Akshay_Budhkar
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1/900
MetalPen
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Sure...
Akshay_Budhkar
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of 90 is 1/900 of 90.. of implies multiplication
Akshay_Budhkar
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so it is
1/900 times 90 = 90/900 = 1/10
MetalPen
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Yes yes I get it.
MetalPen
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That makes sense! Okay that's all! And I have to go. Thank you so much. ^.^
Akshay_Budhkar
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it is my pleasure