# Math Help - Arithmetic Sequence Question

1. ## Arithmetic Sequence Question

Hi this is a Question about AP I've been having trouble about, help would be appreciated.

Q)- The 4th, 6th, and 8th terms of an AP add up to -6. Find the sixth term.

Help would be tremendously appreciated!

2. Originally Posted by SeaNanners
Hi this is a Question about AP I've been having trouble about, help would be appreciated.

Q)- The 4th, 6th, and 8th terms of an AP add up to -6. Find the sixth term.

Help would be tremendously appreciated!
$t_n = a + (n-1)d$.

Therefore $(a + 3d) + (a + 5d) + (a + 7d) = -6 \Rightarrow a + 5d = t_6 = ......$

3. A slightly different way- since we are asked specifically for the sixth term, call that "a". Then, with "r" as the common difference, the fourth term is a- 2r and the 8th term is a+ 2r. Add those together and you will see that the "2r" terms cancel!