Answer
$a)\$ 39.99 \\ b) \$ 46.74\\ c) \$ 40.44$
Work Step by Step
We are given:
$$C(x)=\left\{\begin{array}{ll}
39.99 & 0\leq x\leq 450 \\
0.45x-162.51 & x \gt 450
\end{array}\right.$$
We substitute the given $x$ values into the equation:
$a) C(200)=39.99 \\ b) C(465)=0.45(465)-162.51=46.74\\ c)
C(451)=0.45(451)-162.51=40.44$