Velocity and displacement as a vector

If a particle moves from the point (2, 4) with a constant velocity v = 3i – 4j for 5 seconds

then its displacement vector will be velocity x  time = (3i – 4j) x 5 = 15i– 20j

and so its new position will be given by r = (2i + 4j) + (15i – 20j) = 17i – 16j.