Question

What is the sum of a 12–term arithmetic sequence where the last term is 13 and the common difference is –10?

Answer 1

There is something wrong @Mimi_x3 ..

Answer 2

I think so too lol
I haven't done these in a while..

Answer 3

\[ T_n = a +(n-1)d\]
\[ T_{12} = a + (12-1)*-10 = 13\]
\[ a-120 +10 = 13\]
\[ a -110 = 12\]
a = 122

Answer 4

\[13 = a + (12-1) (-10) \implies 13 = a -110 \implies a = 123\]

Answer 5

What are we doing we don't know @Mimi_x3

Ha hah a..

Answer 6

Another typo lol \(a = 123\)

Answer 7

Sorry brain dead at 2 am.
a -110 = 13 => a =123

Answer 8

So,

\(a = 123\)

Now find the sum..

\[\huge Sum = \frac{n}{2}(a + l)\]

n = 12. a = 123 and l = 13

Calculate the sum now.. @emkaye16

Answer 9

What happens??

Another brain dead?? @Mimi_x3

Answer 10

My internet speed is just as same as that of an ant..

Answer 11

nothing lol

i thought there was another mistake; but there wasnt lol

Answer 12

my brain speed is so slow today :(

Answer 13

@Mimi_x3 I think here we are talking there is no one other watching us..

Ha haha..

Answer 14

lol even the asker is not responding; probably got scared from our mistakes :P

Answer 15

so the answer is 816?

Answer 16

Yes you are right @emkaye16
Sorry I was busy somewhere else..

\[\huge \color{blue}{\textbf{Keep It Up...}} \color{green} {\checkmark}\]