Answer:
1st problem: b) 
2nd problem: c) 
Step-by-step explanation:
1st problem:
The formula/equation you want to use is:

where
t=number of years
A=amount he will owe in t years
P=principal (initial amount)
r=rate
n=number of times the interest is compounded per year t.
We are given:
P=2500
r=12%=.12
n=12 (since there are 12 months in a year and the interest is being compounded per month)

Time to clean up the inside of the ( ).


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2nd Problem:
Compounded continuously problems use base as e.

P is still the principal
r is still the rate
t is still the number of years
A is still the amount.
You are given:
P=2500
r=12%=.12
Let's plug that information in:
.
F(X)=13 Just Plug 10 into the X in the equation
Answer:
It depends how you were taught. You could say it's 11 (eleven) or 2.
2x+4(2x+7)+3(2x+4)
2x+8x+28+6x+12
16x+40
16x+40 would be the answer you can’t solve it any further