WAEC - Further Mathematics (2017 - No. 33)
Given that a = 5i + 4j and b = 3i + 7j, evaluate (3a - 8b).
9i + 44j
-9i + 44j
-9i - 44j
9i - 44j
解释
= \(3(5i+4j) - 8(3i+7j) = 15i + 12j - 24i -56j\)
= \(-9i - 44j\)
= \(3(5i+4j) - 8(3i+7j) = 15i + 12j - 24i -56j\)
= \(-9i - 44j\)