Question

Find the 9th term of the arithmetic sequence.
a_7 = -42 and a_11 = -28; a_9 = ____.

Answer 1

@Numb3r1

Answer 2

OK, if it's arithmetic it's just a matter of addition and subtraction. \[a_9\]is halfway between \[a_7\]and \[a_{11}\]which means that the value will also be halfway between the two.

Answer 3

ok

Answer 4

So that gives you...?

Answer 5

idk

Answer 6

Add them and divide by two. Just take the average!