Answer :
1). You have 12 of something, and 1 of the same thing is taken away.
How many of it do you have then ?
2). You have 3 of something, and 6 more come along.
How many of it do you have then ?
3). Simplified.
1. 12-1 = 11 11a
2. 3+6 = 9 9x
3. 3x-1 (already simplified - not 'like' terms)
2. 3+6 = 9 9x
3. 3x-1 (already simplified - not 'like' terms)