Actually, it's simple and easy.
First you need to determine the instructions; if it is asking for Real Roots, Integral Roots, Fractional Roots or Simply All the Roots.
Real Roots do not include Imaginary numbers. These are the "unfactorable" or simply it cross the definiton of being Imaginary.
Integral Roots for the integers only..
And so on..
Factor Completely. Make sure you factor it, or use the Quadratic Formula.
Then equate each factor by zero.
Then you are done.
Tips: The degree of the polynomial is equal to the number of roots/zeros.
Tips: You can use "multiplicity" then how many times it is repeated.
x^2 = 0
x = 0
x = 0
0 multiplicity 2.