

.
The factors of the absolute value of the constant term,
-10, (which is |-10| or 10):
The factors of the absolute value of the coefficient of the
leading term, 3, the term with the largest exponent,
which is |3| or 3:
Now we make all the fractions possible using one of these
1, 2, 5, and 10 as the numerator and one of these 1 and 3
as the denominator:
Reduce any of them if possible:
Put ± in front of each:
That's the list of all candidates for rational solutions.
Edwin