The rational zeros theorem says that all possible rational (numbers that can be written as fractions) zeros, or x-intercepts, of a polynomial may be found by putting all the factors of the constant over the factors of the leading coefficient.
The constant here is -6, and the leading coefficient is 2.
6 has the factors 1, 2, 3, and 6. 2 only has 1 and 2. Using the positive and negative versions of each fraction, the possibilities are:
± {1/1, 1/2, 2/1, 2/2, 3/1, 3/2, 6/1, 6/2}.
Eliminating the fractions that simplify to the same values, we have ±{1, 1/2, 2, 3, 3/2, 6}.
I hope that helps!
Let me know if you have any questions, and have fun! Pre-calc is awesome!
Liz Z.