To find out of a graph is linear you have to use the vertical line test.
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:
.
X would be 0 and y would be 2 so it would be (0,2)
Answer:
6
Step-by-step explanation:
All sides of triangle EFD have x6 of BAC.
E.g.: BA = 2. ED = 2 x 6 = 12
8 - (-10) = 18
18 / 3 = 6
hope this helps