To prove the statement "If k^3 + 1 is divisible by 3, then k + 1 is divisible by 3" for k \in \mathbb{Z}, we can use direct proof.
Given: k^3 + 1 is divisible by 3.
We want to prove: k + 1 is divisible by 3.
Step 1: Since k^3 + 1 is divisible by 3, we can write k^3 + 1 = 3m for some integer m.
Step 2: Subtract 1 from both sides to get k^3 = 3m - 1.
Step 3: Now, observe that k^3 = (k+1)(k^2 - k + 1).
Step 4: From Step 2, 3m - 1 = (k+1)(k^2 - k + 1).
Step 5: Since the right side of the equation is an integer, k+1 divides 3m - 1.
Step 6: Since k+1 divides 3m - 1 and 3 divides k^3 + 1, we can conclude that k+1 must divide k^3 + 1 as well.
Therefore, if k^3 + 1 is divisible by 3, then k+1 is also divisible by 3.
\boxed{Answer}: k + 1 is divisible by 3.