Answer:
see explanation
Step-by-step explanation:
To find the missing side, subtract the sum of the 2 given sides from the perimeter.
(11)
6x + 6y - (2x + y + x + 2y)
= 6x + 6y - (3x + 3y)
= 6x + 6y - 3x - 3y ← collect like terms
= 3x + 3y ← missing side
(12)
11x + 2y - (2x + 3y + 6x - 5y)
= 11x + 2y - (8x - 2y)
= 11x + 2y - 8x + 2y ← collect like terms
= 3x + 4y ← missing side
