Answer:
6. 8b²-5b-4
7. -3x²+9x-4
8. 3
9. 6a+15
Step-by-step explanation:
you will subtract/add the numbers with the same variables and exponent.
ex. (number 6) 7b²+ b²= 8b²
5b= 5b 8b²+5b-4
1-5= -4
(plus 5b because it didnt come out to a negative) if you have any questions, say in the comments and ill try my best to help
