im learn vector by myself.

i found this questions with answers, but i dunno the step to get that answer.

can anybody help me?

Given vectorsA= (1, 2, -3),B= (3, -4, 0) andC= (0, 3, -4), find the following:

(i)thetaAC

(ii)A·(BxC)

(iii)Ax(BxC)

(iv) (Axj) ·k

Answer:

(i)15.8°

(ii)13

(iii)(54, -57, -20)

(iv)1