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.) 

13 If \( \frac{a}{b}=\frac{b}{c}=2 \), then \( \frac{a}{c}=\ldots \ldots \ldots \ldots \) \( \begin{array}{lll}\text { (a) } 2 & \text { (b) } 4 & \text { (c) } 6\end{array} \)

\( \left\{ \left. \begin{array} { l } { a - 5 < 2 a + 3 } \\ { 3 a - 2 < a - 6 } \end{array} \right. \Rightarrow a \in ? \right. \)

\[ S_{n}=-6+2+10+18+\ldots \] to \( n \) terms. 1. We can find an expression for the general term of the series in the form \( T_{k}=b k+c \). What are the values of \( b \) and \( c \) ? Answer: 1. \( b= \)

23. Find the equation of a line. Whose intercepts on \( x \) and \( y \) axis are 4 and -6 .

b) \( 2 x y-1=5 \) f) \( 3 x x-1=8 \)