Question with exponents! Question attached below...
\[\huge \frac{ (-xy^4)^{-4} }{ -2x^3 \times x^2y^3 }\]
\[(-2x^3)(x^2y^2) \implies -2 \cdot x^{3+2} \cdot y^2 =~?\]
i got the answer of \[\frac{ 1 }{ 2x^9y^19 }\] but the answer key says that it's negative.. i don't know why
Alright let's check each step.
what would you get for : \(\color{#0cbb34}{\text{Originally Posted by}}\) @Jhannybean \[\large (-2x^3)(x^2y^2) \implies -2 \cdot x^{3+2} \cdot y^2 =~?\] \(\color{#0cbb34}{\text{End of Quote}}\)
\[\large -2x^5y^2\]
Alright, and when you distribute the \(-4\) power into every term in the ( ), you expand it like so: \[\large (-xy^4)^{-4} \implies (-x)^{-4} \cdot (y^4)^{-4} = ~?\]
\[\large -x^{-4} \times y^0\]
which is basically like \[\large -x^{-4}\]
\[\large \times \] do you mean this symbol? if so, it's multiplication.
be careful, you wouldnt be adding the exponents here, you'd be multiplying them. \[\large (y^4)^{-4} = y^{4( -4)}\qquad (y^4)^{-4} \ne y^{4-4}\]
oh yes
i still don't understand how you got the negative...
yeah or whose ever work that was posted in the 3 parts
pretty fast eh? ^_^ thinking about making it a tool on OS as an extention
defeats the purpose of Openstudy then.
can you please help me understand why it is a negative?
Ok cotinuing from where we left off.
I just realized theres an easier way to simplify the numerator, check this out
Instead of expanding our numerator first, we can basically turn our entire term WITH the negative exponent into a positive one. \[\large (-xy^4)^{-4} \implies \dfrac{1}{(-xy^4)^4}\] you see how the negatives in the numerator would go away?
So now we expand our numerator, and we get: \[\large \frac{1}{x^4y^{16}}\]
Now we put it over our denominator: \[\large \dfrac{\dfrac{1}{x^4y^{16}}}{-2x^5y^3}\qquad \implies \qquad \dfrac{1}{-2x^{4+5}y^{16+3} } \]
Now whether we have the negative in the numerator OR denominator, it doesnt matter, the fraction altogether is STILL negative.
Do you follow, @calculusxy ?
i am still trying to grasp this.
if we have like complex fractions, then we would have to add the exponents n put it over one?
The only reason we did that, was because we treated \((-xy^4)\) as like a variable... let' say all that junk \(=a\). And then... a is raised to a negative power, and how would we turn that power positive? by putting it over 1. \(a^{-1} \iff \dfrac{1}{a}\)
So if we have a FRACTION in the numerator, and we're DIVIDING it by a term or terms in the denominator, we follow this rule: \[\dfrac{\dfrac{a}{b}}{c} \implies \frac{a}{bc}\]
okay...
i have one other question..
thanks for helping me understand that
Which art are you stuck on? WE'll go from there.
part*
so this time i am getting a negative, but it says that it's a positive. \[\large -\frac{ ba^0 \times -a^3b^3 }{ (ab^0)^{-4} }\]
so i got \[\large -a^7b^4\] but the answer key simply says \[\large a^7b^4\]
@Jhannybean
@jim_thompson5910
@jim_thompson5910 it's the second expression w/ exponents.
oh okay thx !
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