To compute the monthly cost of the cellular phone for 215 anytime minutes used, we need to evaluate the function [tex]\( C(x) \)[/tex] at [tex]\( x = 215 \)[/tex].
Given the cost function:
[tex]\[
C(x) = \begin{cases}
19.99 & \text{if } 0 < x \leq 350 \\
0.20 x - 50.01 & \text{if } x > 350
\end{cases}
\][/tex]
For [tex]\( x = 215 \)[/tex], since [tex]\( 0 < 215 \leq 350 \)[/tex], the cost falls within the first condition of the piecewise function.
Thus,
[tex]\[
C(215) = 19.99
\][/tex]
Therefore, the monthly cost for using 215 anytime minutes is:
[tex]\[
C(215) = \$19.99
\][/tex]
