3. It is early evening. A star appears in the eastern part of the sily. What can be predicted atoou the star muach later at it appears in the northern part of the sky. B. It appears in the southern part of the sky. C. It appears in the same position in the sky. D. I appears in the western part of the sky.

Cuál es el signo de \( 9 \cdot(-0.5) ? \)

Si \( f(x)=\frac{x^{2}-9}{x\left(x^{2}+1\right)} \), entonces el valor de \( \lim _{x \rightarrow \infty} f(x) \)

13. There are about \( 4 \cdot 10^{5} \) known species of beetles. The number of known species of caddis flies is abo \( 10^{4} \). How many times more species of beetles are there than caddis flies?

(1 point) Find all solutions \( x \) to each of the following equations. Separate multiple answers with commas. Use no solution or none if there are no solutions. \( 3 e^{10 x}=5 e^{8 x} \) has solutions \( x=\square \) \( 7 e^{10 x}=4 e^{10 x}+5 e^{8 x} \) has solutions \( x=\square \) \( 7 e^{10 x}=4 e^{10 x}+20 e^{8 x} \) has solutions \( x=\square \) \( \frac{e^{10 x}}{e^{10 x}+5 e^{8 x}}=\frac{4}{7} \) has solutions \( x=\square \)

\( x\left[\begin{array}{ll}x & 7 y \\ z & 4\end{array}\right]=\left[\begin{array}{rr}16 & 28 \\ 13 & 4\end{array}\right] \) \( x=16 \) (Simplify your answer.) \( y=4 \) (Simplify your answer.) \( z= \) (Simplify your answer)