The first thing you should know is that to find the vector, PQ we must subtract both points:
PQ = Q-P = (4, 14) - (2, 9) = (2, 5)
The module of this vector is given by
lPQl = root ((2) ^ 2 + (5) ^ 2)
lPQl = root (29)
answer
PQ = (2, 5)
lPQl = root (29)
