Question 1032313
.
The rational root theorem says that the rational roots of this equation are among the divisors of the constant term, which is 45 in this case.


So, check these numbers: +/-1, +/-3, +/-5, +/-9, +/-15, +/-45.


When you find the root x = n, divide the original polynomial by (x-n)
(long division).


You will get the polynomial of the degree 2 instead of 3.


Then you will be able to complete your analysis.