4. A fruit fly experiment starts with \( 600 \) flies. If the population increases following exponential growth and there are \( 1000 \) flies after \( 2 \) days, how many days will it be until there are \( 10000 \) flies? 

2. Resuelve las siguientes operaciones: a. \( 2 \cdot \sqrt{4 \cdot x^{2} \cdot y}+5 \cdot \sqrt{16 \cdot y^{2}}-21 \cdot x \cdot \sqrt{36 \cdot y^{2}} \)

\begin{tabular}{l} 8. \( f(x)=2 x+3 \) \\ \( x \mid f(x) \) \\ \hline-3 \\ -2 \\ 0 \\ 1 \\ 2 \\ 3\end{tabular}

\begin{tabular}{l} 7. \( f(x)=2 x^{2}-4 x+1 \) \\ \( x \) f(x) \\ \hline-1 \\ 0 \\ 1 \\ 2 \\ 3\end{tabular}

Lös ekvationerna. Skriv på samma sätt som i uppgif \( \begin{array}{ll}118 \text { a) } 3(3 x+4)=39 & \text { b) } 7+4(x-5)=3 \\ 119 \text { a) } 2(9+2 x)=26 & \text { b) } 13+6(x-4)=7\end{array} \)

Priya has a recipe for banana bread. She uses \( 7 \frac{1}{2} \) cups of flour to make 3 loaves of banana bread. Andre will follow the same recipe. He will make \( b \) loaves of banana bread using \( f \) cups of flour. Which of these equations represents the relationship between \( b \) and \( f \) ?