- Find a + b , 2a + 3b , | a | , | a − b | . a = i + 4j − 4k , b = − 4i − j + 5k
- Find a unit vector that has the same direction as the given vector. 4 i − j + 8 k
- Find a vector that has the same direction as ⟨ − 6, 6, 2 ⟩ but has length 6.
- For what values of b are the given vectors orthogonal?

(Enter your answers as a comma-separated list.) ⟨ − 7, b, 3 ⟩, ⟨ b, b^{2}, b ⟩

b =?