Help please. I just need someone to explain to be something about Inequations and inequalities(Parabolas). Please know what your talking about btw :)

Question

aonz · Answer

There is a type of question i always get wrong and i have no idea why,

aonz · Answer

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anonymous · Answer

You forgot to reject the answer $x=0$, since it doesn't work with the original expression (division by zero is undefined).  Your method is correct, though.

aonz · Answer

so x can never equal 0?

aonz · Answer

i feel stupid asking this but why cant x=0?

anonymous · Answer

No, not never.  Just for this problem, since $\dfrac{1}{x}$ is in the original expression.

aonz · Answer

ok i drew a parabola and i got
$$-4\le x \le-\frac{ 5 }{ 2 }$$

aonz · Answer

book says

$$-4<x \le \frac{ 5 }{ 2 }$$

aonz · Answer

original question is
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