How do I answer these questions correctly with steps.

f(x) = x4 - 16x3+ 72x2+ 2 (a) Make a sign diagram for the first derivative. ---Select--- ---Select--- -Select--- -Select--- C ---Select--- X= X (b) Make a sign diagram for the second derivative. ---Select--- ---Select--- ---Select--- ---Select--- ---Select--- E (c) Sketch the graph, showing all relative extreme points and inflection points. 400 400 200 200 -6 -4 - 2 2 4 6 1-6 -2 2 6 IP -200 200 IF IP -400 -400 IP O y 400- IP 400 IP 200 IP 200 IP