Question

Find the 7th term of the arithmetic sequence 3x+7, x+1, -x-5...

Answer 1

-9x - 29

Explanation:

`a_(n)=a_(1)+(n-1) d`

Where,

`a_(n)` is
`a_(7)`

`a_(1)` is 3x + 7

`n` is 7

`d` is (x + 1) - (3x + 7) = -2x - 6

`a_(7)=3x + 7+(7-1) d`

`a_(7)=3x + 7+6( - 2x - 6)`

`a_(7)=3x + 7 - 12x - 36`

`a_(7)= - 9x - 29`