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Work Shown:
To find the perimeter, we add up all the exterior side lengths.
P = perimeter
P = (side1) + (side2) + (side 3)
P = (2y-3x-3) + (12+5x+7y) + (9x-3y+2)
P = (-3x+5x+9x) + (2y+7y-3y) + (-3+12+2)
P = 11x + 6y + 11