For a)

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For b)

I think we can get the minimum point by using Calculus.

Set into

Then

So point P's coordinates is: (3 ; - 25)

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For c)

Now this one really isn't hard.

Look at this:

Would you be able to solve this?

Of course you would!

But look at what i did:

I simply treated as

So let's solve this one:

But remember that is actually equal to

So and

or