Question

Given vectors u=-9i+8j and v=7i+5j find 2u-6v in terms of unit vectors i and j

Answer 1

- 50i - 14j

Explanation:

Substitute u = - 9i + 8j and v = 7i + 5j, that is

2u - 6v

= 2(- 9i + 8j) - 6(7i + 5j) ← distribute both parenthesis

= - 18i + 16j - 42i - 30j ← collect like terms

= - 50i - 14j