Answer:
1. -x
3. 9a-7
5. 14x-2
7. 7d-6
Explanation:
To do the first one you would just subtract 8 by 9 which is -1 so you would get -x as 1.
To do the third one would would just move the numbers around so you get 8a+a-6-1 and when you simplify you get 9a-7.
To do the fifth one you just have to move the numbers so you get -x+15x-2 and when you simplify you get 14x-2
To do the seventh one you just have to move the numbers so you get 8d-d-4-2 and when you simplify you get 7d-6.