B hope this helps good luck
Answer:

Step-by-step explanation:
The amount formula in compound interest is:

where:
P = principal amount
r = annual interest
n = number of compounding periods
t = number of years
We already know that:
P = $2000

t = 7 (number of years from 6th to 13th bday)
n = 4 (quarterly in a year)
Then,

I believe it is 3x+21 but i could be wrong :/ my explaination is -3 • -X would be +3x because it was distributed and -3 • -7 would be +21
I assume that the given equation above is 0.9(x+1.4)−2.3+0.1x=1.6 and not 0.9(x+1.4)−2.3+0.1x=1.60.9(x+1.4)−2.3+0.1x=1.6, I think there is a typo error on this. Based on equation I assumed the answer is 2.64.Thank you for posting your question here, I hope my answer helps.
Answer:
A
Step-by-step explanation:
Hopefully this helps