Trigonometry
8 Online
OpenStudy (anonymous):
what is (1-(4/x))/(1-(2/x)-(8/x^2)) in simplest form? please explain how you get your answer
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OpenStudy (anonymous):
also known as:\[\frac{ 1-\frac{ 4 }{ x } }{ 1-\frac{ 2 }{ x }-\frac{ 8 }{ x ^{2} } }\]
OpenStudy (anonymous):
\[\huge\frac{1-\frac{4}{x}}{1-\frac{2}{x}-\frac{8}{x^2}}\]
OpenStudy (anonymous):
same idea as before find a common denominator
OpenStudy (anonymous):
get the answer is one step by multiplying top and bottom by \(x^2\) cancelling merrily as you go
OpenStudy (anonymous):
ok
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OpenStudy (anonymous):
what satellite73 said works too, and faster
OpenStudy (anonymous):
so...\[\frac{ \frac{ x ^{2} }{ x ^{2} }-\frac{ 4x }{ x ^{2} } }{ \frac{ x ^{2} }{ x ^{2} }-\frac{ 2x }{ x ^{2} }-\frac{ 8 }{ x ^{2} } }\]?
OpenStudy (anonymous):
oh no !!
OpenStudy (anonymous):
what?
OpenStudy (anonymous):
\[\huge\frac{(1-\frac{4}{x})}{(1-\frac{2}{x}-\frac{8}{x^2})}\times \frac{x^2}{x^2}\]
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OpenStudy (anonymous):
distribute
what is \(1\times x^2\) ?
OpenStudy (anonymous):
\[x ^{2}\]
OpenStudy (anonymous):
ok and \(-\frac{4}{x}\times x^2\) ?
OpenStudy (anonymous):
i dont know
OpenStudy (anonymous):
really? don't believe you
\[\frac{-4x^2}{x}=?\]?
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OpenStudy (anonymous):
im confused im sorry
OpenStudy (anonymous):
cancel an x top and bottom or subtract the exponent
either way you get
\[-\frac{4}{x}\times x^2=-4x\]
OpenStudy (anonymous):
oh ok
OpenStudy (anonymous):
so the numerator is
\[x^2-4x\]
how about the denominator?
OpenStudy (anonymous):
ok \[x ^{2}-2x-8x\]is the denominator?
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OpenStudy (anonymous):
close
OpenStudy (anonymous):
\[x^2-2x-8\] the last term is just \(-8\) cause the \(x^2\) cancel
OpenStudy (anonymous):
oh right
OpenStudy (anonymous):
so we are at
\[\frac{x^2-4x}{x^2-2x-8}\] now i think we can factor top and bottom
OpenStudy (anonymous):
ok
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OpenStudy (anonymous):
matter of fact it am sure of it
do you see how to factor the top?
OpenStudy (anonymous):
yes it would be x(x-4)
OpenStudy (anonymous):
and the bottom?
OpenStudy (anonymous):
and the bottom would be (x-4)(x+2)
OpenStudy (anonymous):
then cancel and be done!
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OpenStudy (anonymous):
then you can cancel out the (x-4)s
ok thank you
OpenStudy (anonymous):
yw