Answer:
0.9b + 2
Step-by-step explanation:
First, you'd add 3.8b and -2.9b together, which makes 0.9b. Next, you would add -7 and 9. I say -7 instead of 7 because with minuses before a positive number, you can make it addition and just turn the number after into a negative number instead of positive to make it easier on yourself. Hope this helped.
