Hi Sasha! The first one is correct and polite. 👍👍 "May I be excused from class?" "Can/May I go out" are both used. Usually used when one literally wants to go "out." "Hey mom can/may I go out now?" The old can/may debate is not so strict anymore. However, formally speaking "may" has been seen as more polite. "Can" as a verb alludes to having the ability to do a particular thing. But they both refer to "possibility." I've read a saying in English: "You may use "can" if you wish, and you can use "may" if it makes you feel better." Take good care!

Yes, Its the polite/formal way. Like when you talking to an elder, teacher etc. Can i go is casual way

Can we talk.. I could help you with that,