Answer:
11a^2b^8
Explanation:
Rule 1: The coefficient (121 in this case) has it's square root taken to derive the side.
Rule 2: If a variable with a power is part of the area of a square, then just divide the power by two
The square root of 121 = 11
The square root of a^4 = a^(4/2) = a^2
The square root of b^16 = b^(16/2) = b^8