is it f(x)=3(5/3)^-x ​ a exponential growth function?

is it f(x)=3(5/3)^-x a exponential growth function?

$\begin{array}{rcll} f(x) &=& 3 \cdot \left( \frac53 \right)^{-x} \\ f(x) &=& 3 \cdot \frac{1} { \left( \frac53 \right)^x } \\ f(x) &=& 3 \cdot \frac{1} { \frac{5^x}{3^x} } \\ f(x) &=& 3 \cdot \frac{3^x} { 5^x } \\ f(x) &=& 3 \cdot \left( \frac35 \right)^x \\ \end{array}$

No it is a decaying function, because: $\frac35 < 1$

$y=a\cdot b^x\\ \text{Example: } y = 3 \cdot \left( \frac35 \right)^x$

when a > 0 and the b is between 0 and 1, the graph will be decreasing (decaying).

see: http://www.regentsprep.org/regents/math/algebra/ae7/expdecayl.htm