After discarding any constants of integration, determine the appropriate value of the unknown velocities u or v

Question:

After discarding any constants of integration, determine the appropriate value of the unknown velocities u or v which satisfy the equation of two-dimensional incompressible continuity for:
(a) u = x2y;
(b) v = x2y;
(c) u = x2 – xy;
(d) v = y2 – xy