x^2 + (3k - 1)x + 10 + 2k = 0
We will have real roots as long as the discriminant is ≥ 0
So
(3k - 1)^2 - 4 (1) ( 10 + 2k) ≥ 0
9k^2 - 6k + 1 - 40 - 8k ≥ 0
9k^2 - 14k -39 ≥ 0
(9k +13) (k - 3) ≥ 0
This will be true for k on the intervals (-inf , -13/9 ] and [3 , inf )