## Algebra 2 Common Core

$\text{exponential growth;}$ $y$-intercept = $\dfrac{7}{8}$
Recall: The exponential function $y=c \cdot b^x$ involves exponential: (i) growth when $b\gt 1$ (ii) decay when $0 \lt b \lt 1$ The given exponential function has $b=18$, which is greater than $1$, therefore it involves exponential growth. The $y$-intercept of a function can be found by setting $x=0$ then solving for $y$. Set $x=0$ then solve for $y$ to obtain: \begin{align*} y&=\frac{7}{8}\left(18\right)^x\\\\ y&=\frac{7}{8}\left(18\right)^0\\\\ y&=\frac{7}{8}(1)\\\\ y&=\frac{7}{8} \end{align*} Thus, the $y$-intercept is $\dfrac{7}{8}$.