1. 11s²-21st
2. 4st-t²
3. 2x²+x³
4. 2x+2
5. 9x-3s-2t
6. 95x-1
7. 9x-2
8. 7s
9. 12-10x
10. 33x-4
11. 10t
5.7m questions
7.5m answers