Question

HELP !!

In a sequence of numbers, a4=9, a5=15, a6=21, a7=27, and a8=33.

Which recursive rule can be used to find the nth term of the sequence, an?


a1=−9; an=an−1+6

a1=−9; an=6an−1

a1=9; an=an−1+6

a1=9; an=6an−1

Answer 1

Given sequence:

• a₄=9, a₅=15, a₆=21, a₇=27, and a₈=33

Common difference is:

• 33-27 = 27 - 21 = 21 - 15 = 15 - 9 = 6

Find the first term:

• a₃ = 9 - 6 = 3
• a₂ = 3 - 6 = - 3
• a₁ = -3 - 6 = -9

Recursive formula:

• a₁ = -9 and aₙ = aₙ₋₁ + 6

Correct choice is A