10.

(a) Show the associative property for the OR operation using Venn diagrams with x, y, and z overlapping regions. Sketch the following regions to show that region (3) is the same as region (6):

(1) (x + y)

(2) z

(3) (x + y) + z

(4) x

(5) (y + z)

(6) x + (y + z)

(b) Do the dual of part (a).