Proof Writing & Problem Solving · Easy problem

The inductive step for "$3 \mid n^3 + 2n$ for all $n \ge 1$" computes the change from $n = k$ to $n = k + 1$: $\big((k+1)^3 + 2(k+1)\big) - (k^3 + 2k) = 3k^2 + 3k + 3$, a multiple of $3$. What is this change when $k = 5$?