In a recent year, the cost per ton, y, to build an oil tanker of x thousand deadweight tons was approximated by

for x > 0.
(a) Find C(25), C(50), C(100), C(200), C(300), and C(400).
(b) Find any asymptotes on (-∞, ∞).
(c) Find any intercepts.
(d) Graph y = C(x) over all x for which C(x) is positive.

C(x) = = 220,000 x + 475