Hi there! Just struggling on a couple of revision questions - would you be able to help me solve them and show the steps?

Firstly, If a = (2, ?3, 1, ?4) and b = (?3, ?1, 5, ?2)

1. what is (2a ? 2b) ?
2. what is (2a ? 2b)* (2a + 2b) ?
3. what is || a || and || b || ?
4. How would we show that the triangle inequality applies in this case?

Secondly, how do we calculate the determinant of A (referencing the photo)

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