A telephone company offers a monthly cellular phone plan for $30.00. It includes 350 free minutes plus $0.25 per minute for additional minutes. The following function gives the monthly cost for a subscriber, where x is the number of minutes used. C(x) = { 30.00 30.00 +0.25(x-350) if 0 x 350 if x350 Simplify the expression in the second line of the piecewise function. Then use point-plotting to graph the function