#1 [A-4 points, T-3 points) Shadib operates a printing machine and the cost, in dollars, of operating this machine per day
is given by the formula C = 21 - 84t + 1025 where t is the time, in hours, the machine
operates.
a) What is the minimum cost of running the machine and for how many hours must the machine
run to reach the minimum cost?
b) On a certain day the cost of running the machine was estimated to be close to $300. For how
many hours could the machine have been operating on that particular day? Fully explain your
answer.