A long-distance telephone service charges $0.07 for the first minute (or any fraction thereof) and $0.05 for each additional minute (or fraction thereof).
(A) Write a piecewise definition of the charge R(x) for a long-distance call lasting x minutes.
(B) Graph R(x) for 0 ≤ x ≤ 6.
(C) Is R(x) continuous at x = 3.5? At x = 3? Explain.