exponents

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This whole term is in brackets, I don't know how to make the BIG brackets.

(3w^2 over w^4x^3) ^-2 I started this one by breaking it down to
(3w^2)^-2 over
(w^4x^3)^-2

3^-2w^-4
w^-8x^-6

3^-2 is -9, this is where I feel I got stuck. I have the -9*w^-4*w^-8*x^-6 since my two w's are like terms I want to combine them but I don't know if that is right. Any suggestions?
 
Hi bethany,

First off, 3^-2 is not equal to -9. Remember that a^-x=1/(a^x), so 3^-2=1/(3^2)=1/9


"(3w^2 over w^4x^3) ^-2 I started this one by breaking it down to
(3w^2)^-2 over
(w^4x^3)^-2"

That's correct. From this point, try doing what I showed you above, and then simplifying it, and see how far you get.
 
Drat! I remember that.

Okay, so I have 1/9* w^-4* w^-8* x^-6 multiplication means addition so I have 1/9*w^-12*x^-6 Right?
 
Hello, bethany3168!

\(\displaystyle \L \left(\frac{3w^2}{w^4x^3}\right)^{-2}\)

I started this one by breaking it down to: .\(\displaystyle \L \frac{(3w^2)^{-2}}{(w^4x^3)^{-2}} \;= \;\frac{3^{-2}w^{-4}}{w^{-8}x^{-6}}\) . . . . right!

\(\displaystyle 3^{-2}\) is -9 . . . . no
This is where I feel I got stuck.

I have: \(\displaystyle (-9)(w^{-4})(w^{-8})(x^{-6})\) . . . . you lost the division
Go back to: .\(\displaystyle \L\frac{3^{-2}\cdot w^{-4}}{w^{-8}\cdot x^{-6}}\)

Now, anything with a negative exponent gets "moved".
. . If it is in the numerator, it moves to the denominator.
. . If it is in the denominator, it moves to the numerator.
In both cases, remember to change the exponent to positive.

So we have: .\(\displaystyle \L \frac{w^8x^6}{3^2w^4}\)

Now you can combine the \(\displaystyle w\)'s and simplify: . \(\displaystyle \L\frac{w^4x^6}{9}\)

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

By the way, did you know that a negative exponent on a fraction
. . will "flip" the fraction?

Example: . \(\displaystyle \L\left(\frac{a}{b}\right)^{-3} = \;\left(\frac{b}{a}\right)^3\)

Simplify it the 'normal way': .\(\displaystyle \L\left(\frac{a}{b}\right)^{-3} = \;\frac{a^{-3}}{b^{-3}} \;= \; \frac{b^3}{a^3}\)

But this is the same as: . \(\displaystyle \L\left(\frac{a}{b}\right)^{-3} = \;\left(\frac{b}{a}\right)^3 \;= \;\frac{b^3}{a^3}\)


Your problem could hae been: . \(\displaystyle \L \left(\frac{3w^2}{w^4x^3}\right)^{-2} = \;\left(\frac{w^4x^3}{3w^2}\right)^2\)

. . and eliminate the negative exponents in the very first step!
 
I think you guys should get together and publish a text! Why can't they just show that in the book???

Thank you so much. I have honestly learned so much more on this site than I have in the last 10 weeks of class.
 
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