Answer:
#3's answer is C
#4's answer is B
Step-by-step explanation for #3:
1. Combine like terms: 2a - a - 9b + 3 - 7
2. Solve: a - 9b - 4; answer C
Step-by-step explanation for #4:
1. Distribute 2 to p + 3: 2p + 6
2. Combine like terms: 2p - 8p + 6 + 13
3. Solve: -6p + 19; answer B
