Case 1: If p is 3 then p²+8=17 and p³+4=31,
so it is true in this case.
Case 2: If p>3 then either p=3k+1 or p=3k-1 for some integer, k.
If p=3k+1 then p²+8 = 9k²+6k+9, which is a multiple of 3
and therefore not prime.
If p=3k-1 then p²+8 = 9k²-6k+9, which is also not prime.
So the statement is true (vacuously) in this case as well.
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