I will take the self-taught exam soon, but I can't do an economic application problem. Please tell me the process of solving the problem, thank you.

FC=70

AC=TC/Q= Q2-4Q+ 100+70/Q

VC=TC-FC= Q3-4Q2+ 100Q

AVC=VC/Q= Q2-4Q+ 100

MC=dTC=3Q2-8Q+ 100