First method to determine answer is to use FOIL method -
18 u v = 18 (2-2i) (1-1i) = 18 (2-2i-2i-2) = 18 (-4i) = -72i, this means magnitude of 72 units along the i - axis pointed down from the orgin.
Second method to do this involves multiplying phasors (multiply magnitudes and add angles).
u = (2-2i) = 2SQRT(2) @ 315 deg
v = (1-1i) = SQRT(2) @ 315 deg
18 u v = 18 * 2 * SQRT(2)^2 @ 630 deg = 72 @ 270 deg. this means 72 units along the i - axis pointed down from the origin.
hope this helps!