Chapter 12 - Exponential Functions and Logarithmic Functions - 12.5 Common Logarithms and Natural Logarithms - 12.5 Exercise Set - Page 818: 78

$-\displaystyle \frac{15}{2}$

$(f+g)(x)$ is a new function obtained by combining $f$ and $g$ so that $(f+g)(x)=f(x)+g(x).$ $(f+g)(0)=f(0)+g(0)$ $=\displaystyle \frac{1}{0+2}+5(0)-8$ $=\displaystyle \frac{1}{2}-8$ $=-\displaystyle \frac{15}{2}$