-30 3 -1 -a-b (x-y+4)(x-y-2) 12 2 25 42 90 15 2 4 1 2x

-30
(x-y+4)(x-y-2)
-a-b
3
-1
2
2x+3
a+1
90
4
42
12
15
2
1
25