Question

Please help? Will give fan and medal.
Write the arithmetic series in summation notation. 5+10+15+20+25+30+35 =?

Thank you in advance!!

Answer 1

so u got all the values....u just need to plug them in the equation :))

Answer 2

Okay. So how? :)

Answer 3

\[S_n = \frac{ n }{ 2 }(a_1 + a_n)\]
\[a_1 = 5~~and~~a_n = 35~~~and~~n = no ~~of~~ terms ...\]

Answer 4

count the no of terms :))

Answer 5

Okay, thank you!

Answer 6

u welcome :)

Answer 7

Is it, n = 140/s?

Answer 8

n is the no of terms ...
so n = 7

Answer 9

so it means
\[S_7 = \frac{ 7 }{ 2 }(5 + 35)\]

Answer 10

@Ray1998 oops did u mean S_n = 140 ???
i mean the sum??

Answer 11

Yes. :)

Answer 12

no no there would be 7

Answer 13

140 is the value of sum of tht sequence

Answer 14

7 goes where I have the 140?

Answer 15

And the 140 on the side?

Answer 16

tbh not sure about the ...bt 7 goes where u plugged 140

Answer 17

Okay. Thank you :)

Answer 18

u welcome :))

Answer 19

And if you're not busy, could you help me with some more?

Answer 20

I could start a new question so that you could get credit for each one :)

Answer 21

here u go :)))

http://prntscr.com/ajoywq

Answer 22

Oh! Yes :) I got it ^.^ but thank you for screenshotting it to show me.

Answer 23

u welcome :))