Tolong bantu dijawab ya beserta jalannya...

d = k c dengan k < 0 karena berlawanan
c = 16i - 15j + 12k =>
|c| = √(16^2 + (-15)^2 + 12^2) = √(256 + 225 + 144) = √625 = 25
|d| = 75 = 3 . 25 => 3 |c|
k = -3
d = -3c = -3(16i - 15j + 12k) = -48i + 45j - 36k