Chapter 5 - Exponential Functions - 5.5 Exponential Growth and Decay Rates and Compounding Interest - 5.5 Exercises - Page 469: 8

$8\%$ decay.

Growth or decay rate $r=b-1$ where $r$ is a percentage written as a decimal and $b$ is the base of an exponential function of the form $f(x)=a\cdot b^{x}$. Given $f(x)=150(0.92)^{x}$ $\implies b=0.92$ $r=b-1=0.92-1=-0.08$ Or $r=-0.08\times100 \%=-8\% $ $r$ is negative. So, there is $8\%$ decay.