-First question: https://gyazo.com/eb3f9ef4cc667878c2534fa1624fd00c

-Second question: https://gyazo.com/67f974894ab9eccc8c33af724e4192ac

For the first question, I have no idea what should I do to start the question, so guidance is appreciated.

For the second question, what I attempted was to do moment of Inertia of the whole shape - moment of inertia of the void (slots). But I don't get the right answer.

I post my working out for the second question.

https://gyazo.com/df5ebaeef87fa8dd20a7c11c4a555ac0

I'm really stuck with these questions so I really would be glad to get some help!