Question

What is the explicit formula for this sequence?
-9.-3,3,9, 15. ...

Answer 1

For an nth term U(n) = a + ( n - 1)d

n = number of terms

a = first term

d = common difference

a = -9

d = -3--9 = -3+9 = 6

U(n) = -9 + (n - 1)6

That's option A.

Hope this helps.