Answer:
1. $25
2. 12
3. -12
4. -12
5. -25
Step-by-step explanation:
Answer:
The equation for the nth term of the given arithmetic sequence is: 
Step-by-step explanation:
We need to write an equation for the nth term of the arithmetic sequence:
15,28,41 ....
The equation for arithmetic sequence is: 
Where
is the nth term,
is first term and d is common difference
In the given sequence we have:
a₁ = 15
a₂ = 28
We can find common difference using the formula:

So, the common difference d is 13
Now, equation for nth term will be:

So, the equation for the nth term of the given arithmetic sequence is: 
where n=1,2,3..
I don't think it's proportional, because in order for a question to be a proportional question has/could be to be like this:
Gasoline costs $2.79 per 2 gallon. How much will it cost for 8 gallon. Then, we cross multiply and all to find the answer.
x and x+4 are the numbers
3x=2(x+4)
3x=2x+8
3x-2x=8
x=8
x+4=12