Question

Given an arithmetic series with a1 = 70 and the sum of the first 12 terms = 576. What is d?

Answer 1

Arithmetic series formula:
\[T_n = a+(n-1)d\]
Given:
a_ 1 = 70 ; and the first 12 terms is 576 so...
\[ T_{12} = 70 + (12-1)d = 576\]
Are you able to do it now? :)

Answer 2

should i add 72+12/576

Answer 3

You are solving for \(d\) so you expand \((12-1)d\)

And where did \(72\) come from? :/

Answer 4

I meant 70

Answer 5

Well .. \( 70+(12-1)d = 576\)
Can you expand the \((12-1)d\) first?

Answer 6

11

Answer 7

how do i expand it