Solution

Observation from the diagram:

• The region outside both circles is shaded.
• The overlapping (intersection) region of a and b is shaded.
• The non-overlapping parts of the circles are not shaded.

Step 1: Identify shaded regions

Shaded regions =
• Intersection of a and b → ab
• Outside both a and b → a'b'

Therefore,
Expression = ab + a'b'