Question 277511
simplify 4 + x^-1
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64+ x^-3 
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I factored the terms and made the exponents positive. 
4+x^1
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(4+x)(4-x)(4-x) 
x^3 minus x = x^2 which is the numerator of the answer. 
(4+x) is cross cancelled leaving the denominator of the answer to be 16. 
I think the answer is 
X^2
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16 
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x^-1 = 1/x
x^-3 = 1/x^3
{{{64+x^-3 = 4^3 - (1/x)^3}}}
= {{{(4 + (1/x))*(16 - (1/x) + (1/x)^2)}}}
The numerator is the 1st term, so cancel those.
--> {{{1/(16 - (1/x) + (1/x)^2)}}}
or {{{1/(16 - x^-1 + x^-2)}}}
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I factored the terms and made the exponents positive. *** Changing the exponents is not allowed.