(i) Draw the line x + y = 3. Shade the region of the rectangle enclosed by the line. Integrate the joint pdf over that region. From the sketch it should be clear that:
Note: You should not be attempting questions like this until you have learnt how to evaluate double integrals.
(ii) You should know that .
Draw the horizontal line y = 5/2. Draw the vertical line x = 3/2. Then it should be clear that: