Your inequality is: -15 < -3k - 2k
Start by subtracting 2k from -3k because they are the same term: -3k - 2k = -5k. Now you have: -15 < -5k.
Now divide both sides by -5. Remember that whenever you multiply or divide by a negative number, you flip the inequality sign:
-15 < -5k
3 > k
Your answer is k < 3 (which is the same thing as 3 > k).
