Question

pls answer i will mark brainliest too!!

Answer 1

Answer:

a = 2

Explanation:

A = i + 3 j + k

B = 2i - aj + 4 k

A.B = 0

$(i + 3j + k).(2i - aj + 4k) = 0 \\ \\ 2 - 3a + 4 = 0 \\ \\ 6 - 3a = 0 \\ \\ 3a = 6 \\ \\ a = \frac{6}{3} \\ \\ a = 2.$