A3. Solve the inequality $\frac{10}{x^{2}+4} \leq 0$. Which numbers are solutions?
(A) $x \in[-2,2]$
(B) $x_{1}=2, x_{2}=-2$
(C) $x \in(-\infty, 2)$
(D) $x \in(0,5)$
(E) The inequality has no solutions.
A3. For every real number $x$, $x^{2}+4 \geq 4>0$, so the given fraction has a positive value for every $x$. For no real number $x$ does it have a value less than or equal to 0.