The number of minutes that a flight from Phoenix to Tucson is early or late is a random variable whose probability density is given by
where negative values are indicative of the flight's being early and positive values are indicative of its being late. Find the probabilities that one of these flights will be
(a) at least 2 minutes early;
(b) at least 1 minute late;
(c) anywhere from 1 to 3 minutes early;
(d) exactly 5 minutes late.