When answering a problem like this, normally, you first isolate the absolute value. As it is already isolated, the next thing you do is split the equation into 2k + 1 ≥ 5 and 2k + 1 ≥ -5, because the contents of the absolute value could be negative or positive, and simplifying both into k ≥ 2, and k ≤ -3.
