What are the eigenvalues of the matrix A = { (2,1, 0) , (1, 2, 0) , (0,1,2) }?

Please show me how to get the eigenvalues. I got as far as subtracting the identity matrix from A and calculating the det (A), not sure if it is correct but my answer is 6 - 11 (lambda) + 6 (lambda)^2 - lambda ^ 3. Now I know I have to factor this but I don't know how to.