you have 2 terms - j & k
If you're multiplying terms with the same base, you can add the exponentials.
In this case, you have j^2 * j^1 and k^3 * k^2. Because the j and k terms have the same base, that makes:
j^3k^5
So simplified, (j^2k^3)(jk^2) = j^3k^5