# Let u = 5i - j + k, v = j - 5k, w =-15i + 3j - 3k. Which vectors, if any, are (a) perpendicular? (b) Parallel? Give reasons for your answers.

Question

Let u = 5i - j + k, v = j - 5k, w =-15i + 3j - 3k. Which vectors, if any, are (a) perpendicular? (b) Parallel? Give reasons for your answers.