Answer
$\text{exponential decay}$;
$y$-intercept = $3$
Work Step by Step
RECALL:
The exponential function $y=c \cdot a^x$ represents an exponential:
(i) decay when $0\lt a \lt 1$;
(ii) growth when $a \gt 1$
The given exponential function has $a=0.25$ which is less than $1$.
Thus, the given function represents exponential decay.
The $y$-intercept of a function can be found by sestting $x=0$ then solving for $y$.
Hence, the $y$-intercept is
\begin{align*}
y&=3 \cdot (0.25)^x\\
y&=3 \cdot 0.25^0\\
y&=3 \cdot 1\\
y&=3
\end{align*}
