Atelephone company offers a monthly cellular phone plan for $ 39.99 it includes 300 anytime minutes plus $ 0.25 per minute for additional minutes.

the following function is used to compute the monthly cost for a subscriber, where x is the number of anytime minutes used.

upper c left parenthesis x right parenthesis equalsc(x) =39.99
if 0 less than x less than or equals 3000 < x ≤300
0.25 x minus 35.010.25x−35.01
if x greater than 300x > 300
compute the monthly cost of the cellular phone for use of the following anytime minutes.
(a) 170=$
(b) 335=$
(c) 301=$