Answer:
b = 3, which is an extraneous solution because if we replace b = 3 in the equation, we must be 5/0 and 30/0, and there is division by 0.
Step-by-step explanation:

The minus common multiply must be (b-3)*(b+3) = b² - 9

7b - 21 + 5b + 15 = 10b
2b = 6
b = 3
Which is an extraneous solution because if we replace b = 3 in the equation, we must be 5/0 and 30/0, and there is division by 0. So this solution is invalid.
Presently ratio is at 10:18 = 1.25
With 5 more girls & guys joining, ratio would change to 15:13 = 1.153846154
Therefore, the ratio of girls to boys would change rather not remain the same.
I can’t read the question, what is the question?
Answer:
Interest would be $15 every 3 years
Step-by-step explanation:
Interest = Principal x Rate x Time
Interest = 100 x 5% x 3
Interest = 5 x 3
Interest = 15