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.
Answer:
7^9
Step-by-step explanation:
The way to solve this question is to essentially reverse the equation I used in the other answer.
I would solve this with some theoretical values. If you start with 3, how long would it take for it to triple, or reach 9.
the equation would look like 9 = 3(2)^t/6, note how the instead of 1/2 it is now 2 in the parenthesis, as it doubles every 6 hours rather than halves every amount of hours.
When placed into an algebra calculator, the answer should be about 9.5 hours
Answer:
$337.05
Step-by-step explanation:
450 x (1- 0.3)= $315
$315 x (1+0.07)= $337.05