If D = (3.00î − 4.00ĵ) m, B = (−5.00î + 4.00ĵ) m, and A = (18.0î − 8.00ĵ) m, find the unknown constants a and b such that aD + bB + A = 0.

Answer 1

Just set up equations for the components:
3a - 5b + 18 = 0
-4a + 4b - 8 = 0
Now just solve for a and b.