Question 5 is literally testing whether you understand Lagrange multipliers.

We're not going to give you the answers; you have to show us what you have done and where you are stuck, and we will help you understand.

Question 1 does not make sense mathematically. You need to ask whomever wrote it what it is supposed to mean, because to my knowledge, x cannot simultaneously be a variable of integration

*and*a limit of integration. Same with y.