Question

Find an equation for the nth term of the arithmetic sequence. -15, -6, 3, 12,.

Answer 1

T(n) = 9n - 24

Explanation:

The first term is -15, therefore a = -15

The difference between the 1st and 2nd term is 9, therefore d = 9.

Set up the equation with T(n) = a + (n-1)d

T(n) = -15 + (n-1)(9) = 9n - 24