Answer:
15(b+2) + 15 + 2b-9 +b = 90
Step-by-step explanation:
Essentially you add up all of the values and make it equal to 90, then solve for b
15(b+2) + 15 + 2b-9 +b = 90
15b + 30 + 15 + 2b - 9 + b = 90
18b + 30 + 15 - 9 = 90
18b + 36 = 90
18b = 54
b=3