I need help answering part of this two questions ..

i got some correct nut i did not know how to do the rest ???

need help with explanation if you can

Thanks

Find the critical pointis) and the interval on which the given function is increasing or decreasing. and apply the First Derivative Test to each critical point. Let f(x) = 2x3 12x2 There are two critical points. If we call them a, and (:2. with (:1