Advanced Math.
posted by Jamie .
List the possible rational roots of 2x^3 + 17x^2 + 23x  42 = 0
My answer: the possible rational roots are {±1, ±2, ±3, ±6, ±7, ±14, ±21, ±42. ±1/2, ±3/2, ± 7/2, ±21/2}.
Correct?

yes, and guess what?
x = 1 works!
after a quick synthetic division I got
2x^3 + 17x^2 + 23x  42 = 0
(x1)(x^2 + 19x + 42) = 0
and that quadratic factors very nicely again. 
Yes, this is what you get when you apply the Rational Roots theorem.
But your list is very long, so it is of little use. It is a bit like answering the question by saying that all possible rational roots are the members of Q (as the problem didn't specifically say to list all the roots that the Rational Roots theorem yields). 
Incorrect