These are the two problems from my homework I don't get.. can you help me?

Question

A: y=2x-x^3 [0,1] use the limit process to find the area of the
region between the graph of the function and the x-axis over the
given interval. Sketch the region

B: f(x)=4-(12/(x^2))Calculate the lower and upper sum estimates of the area under the curve over the interval [2,5] using subintervals of width ½.

Thanks!