Step-by-step explanation:
I've posted solutions in the picture. Rather the ways to solve them. Check and find answers on your own.
Also, I've not solved the problem by differential calculus. You can, obviously, if you're interested. Use it for ease and for tougher equations.
Answer:
sry I just wanted the points I'm in middle school so I don't know this stuff either but can you give free brainlyest I'm soo close to my next rank I'd really appreciate it if you would