Question

Find the 7th term in the sequence?
-1,-3,-9

Answer 1

Answer: -21, what ever number you have you subtract 3 from that number. So after -9 would be -12 and so on

Answer 2

-729

Explanation:

Given is a geometric sequence.

Therefore,

a = - 1, r = - 3 /(-1) = 3, n = 7

`a_7 =?`

`\because a_n = ar^(n-1)`

`\therefore a_7 = (-1)(3)^(7-1)`

`\therefore a_7 = (-1)(3)^(6)`

`\therefore a_7 = (-1)(729)`

`\therefore a_7 = -729`