Write the first 5 terms of the arithmetic sequence if the nth term is given by 25+(n-1)(7)

Here, Just substitute the value of n, 
a(1) = 25 + (1-1)(7) = 25
a(2) = 25 + (2-1)(7) = 32
a(3) = 25 + (3-1)(7) = 39
a(4) = 25 + (4-1)(7) = 46
a(5) = 25 + (5-1)(7) = 53

In short,  Your Sequence would be 25, 32, 39, 46, 53

Hope this helps!

These are the multiples of 15 but what you are probably asking or what are the factors of 15