Question 220158
{{{f(x)= (x^4+4)/(x^2+6x-16)}}}
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They are right.
Here's why.
Your domain is all real values of x EXCEPT x = -8 and x = 2
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(-{{{infinity}}},8) covers the interval from minus infinity < x < -8.
(2,{{{infinity}}}) covers the interval from 2 < x < infinity.
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you are missing the interval from -8 < x < 2 represented by:
(-8,2)
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number line would show that as follows:
-{{{infinity}}}-----------------------(-8)---------------------(2)----------------{{{infinity}}}