The function t(x) = 0.15(x-3000)+ 300 represents the tax bill t of a single person whose adjusted gross income is x dollars for income between $3000 and $68, 200, inclusive.

(a) what is the domain of this linear function?
(b) what is a single filer's tax bill if the adjusted gross income is $16,000?
(c) which variable is independent and which is dependent?
(d) graph the linear function over the domain specified in part (a).
(e) what is a single filer's adjusted gross income if the tax bill is $4170?