(2a+y) + (9a-y)
(8x-6) - (2x-3)
(9b-5) + (6b-9)
(2a-6) - (6a-7)
(7x-4) - (8x-4)
(7x-7) - (9x+8)
(6a) - (3b)
(3y+4) + (5y-5)
(9y-3) + (5y+5)
(3y+7) + (4y-5)
x+8
14y+2
7y+2
6a-3b
11a
15b-14
-2x-15
-4a+1
6x-3
8y-1
