Without graphing, determine whether the function represents exponential growth or exponential decay. Then find the \( y \) -intercept. \( f ( x ) = 4 ( 0.65 ) ^ { x } \) Choose the correct answer below. The function represents exponential decay. The function represents exponential growth. The y-intercept is \( \square \) . (Type an integer or a decimal.) 

In the expansion \( \left(\sqrt[3]{2}+\frac{1}{\sqrt[3]{3}}\right)^{n} \) if the ratio between the seventh term from the beginning to the seventh term from the end \( 1: 6 \), then \( n \) equals \( \begin{array}{llll}\text { (a) } 7 & \text { (b) } 8 & \text { (c) } 9 & \text { (d) } 10\end{array} \)

Rationalize the denominator of \( \frac{7}{2 + \sqrt{3}} \).

Solve for \( a \) in the proportion. \[ \begin{array}{l}\frac{19}{a}=\frac{9.5}{6} \\ a=\square\end{array} \]

Solve the equation: \( \sqrt{x + 4} = 6 \)

Determine the values of \( x \) and \( y \), in the equation: \( \frac{x-1}{3+i}+\frac{y-1}{3-i}=i \). Solve the following equations: i) \( 2^{2 x+1}=3^{2 x-5} \quad \) ii) \( \log _{2} x-\log _{2} y=2 \) \( \log _{2}(x-2 y)=3 \) In a senior secondary school, 80 students play hockey or football. The number that plays football is 5 more than twice the number that play hockey. If 15 students play both games and every student in the schoo plays at least one game, find the number of students that play football.