2a-b
9xy-30x-15y+1
920y
-18y2-56y
-2x-1
-2a+3b
2x+12y+9
79xy-2512x-12y
-2a+14
-x2+12x-2
2ab+15a-17b
-3a+2b
-7ab-212a+283
52x2+34y-43
-54x-8
a-1
-2a-6310b
-198x+94
3x4+54
a6-b6
27x4-214
2x3-2y3
-16a4b3
-6m3n4
96x2y2z2
-5a2b4c4
-18ab4c3
-x7y8z948
36x3y6
3x7y8
2a
-6a2
-8p2q7r83
9a2
12x
2ab23c
b32ac2
3200b
2a29b
xy4
2xy2z