1. What are we supposed to do with this? Also, where does t fit in? You never specified anything about it.
2. If you make a quick sketch of the graph, you'll see that there are two regions in which they are bounded: from -2 to 0 (where y = x^3 is bigger than y = 4x) and from 0 to 2 (where y = 4x is bigger than y = x^3).
So, the areas bounded by both curves: