The consumption function in a certain economy is given by
$$\begin{array}{l}\text { The to the } \\\qquad \begin{array}{ll}\text { (?) }=0.75 y+6 \\\text { (?) } 557\end{array}
\end{array}$$
where $C(y)$ is the personal consumption expenditure, $y$ is the disposable personal income, and both $C(y)$ and $y$ are measured in billions of dollars. Find $C(0), C(50),$ and $C(100)$.