Question

Find the nTH term of this sequence: 15, 12, 9, 6

Answer 1

-3n + 18

Explanation:

an = dn + (a - d)

The difference is -3.

The first term is 15.

an = -3n + (15- (-3))

an = -3n + 15 + 3

an = -3n + 18

Answer 2

aₙ= 18 -3n

Explanation:

15, 12, 9, 6

Given AP with first term= 15 and common difference= -3

aₙ=a₁+(n-1)d= 15+(n-1)*(-3)= 15 - 3n+3= 18-3n

aₙ= 18 -3n