1) 2x+y
2*3+2 < 2x+y < 8*2+6
8 < 2x+y < 22
2) xy
3*2 < xy < 8*6
6 < xy < 48
3) x-y
3-2 < x-y < 8-6
1 < x-y < 2.
1) 2x+y
2*3+2 < 2x+y < 8*2+6
8 < 2x+y < 22
2) xy
3*2 < xy < 8*6
6 < xy < 48
3) x-y
3-2 < x-y < 8-6
1 < x-y < 2.