Answer
a) $f(6)+ g(6) = 45 $
b) $f(g(7))=-26.5$
c) $f(3)g(3)=-9.5 $
Work Step by Step
Given \begin{equation}
f(x)=\frac{1}{2} x-1 \text { and } g(x)=-8 x+5.
\end{equation} A) Do the required subtraction and find $f(6)-g(6)$.
\begin{equation}
\begin{aligned}
f(x)-g(x)& = 0.5x-1-(-8 x+5) \\
& =0.5x-1+8x-5 \\
& = 8.5x-6\\
f(6)-g(6) & = 8.5\cdot 6-6\\
& = 45.
\end{aligned}
\end{equation} B) Find $f(g(7))= f(-51)$ where $g(7) = -8\cdot 7+5= -51$.
\begin{equation}
\begin{aligned}
f(g(-51))& =0.5\cdot (-51)-1\\
& = -26.5.
\end{aligned}
\end{equation} C) Multiply $f(3)g(3)$.\begin{equation}
\begin{aligned}
f(3)& =(0.5)\cdot(3)-1=0.5\\
g(3)& = -8\cdot 3+5= -19\\
f(3)\cdot g(3)& =(0.5)\cdot(-19)\\
& = -9.5.
\end{aligned}
\end{equation}
