Question

need help with arithmetic series

Answer 1

\[{A}_1=4; d=7; S _{n}=228=EC\]

Answer 2

Please help me solve step by step so i know what to do for others.

Answer 3

@Hero

Answer 4

anyone???

Answer 5

you here wanna find (n) value, right?

Answer 6

that and athe upside down ^n

Answer 7

\[S_{n}=\frac{ n }{ 2 }(2a_{1}+(n−1)d)\]
Use this formula to find n

Answer 8

you know how to do it, right?

Answer 9

no not really

Answer 10

ok you have (a) value which is =4
and also have d-value = 7
and have Sn=228
So plug each value into your formula and tell me what you got

Answer 11

228=n/2(2(4)+(n-1)7)

Answer 12

correct?

Answer 13

yea since you have only one variable now you have to solve it for (n)

Answer 14

k how

Answer 15

\[228=\frac{ n }{ 2 }[(2\times4)+(n-1)\times7]\]
\[228=\frac{ n }{ 2 }(8+7n-7)\]
Multiplying both sides by 2 :
\[456=8n+7n^2-7n\]
arrange now you get :
\[7n^2+n-456=0\]
Final step is to get n value(tell me if you don't know how to do it)

Answer 16

is 0 An?

Answer 17

or am i missing soemthing from this

Answer 18

something8

Answer 19

something*

Answer 20

yea it will be 8

Answer 21

wait N is 8

Answer 22

\[S _{n}=228\]
\[S _{8}=228\]

Answer 23

ok csn you do like a recap of the whole thing so i can write this down so i dont miss anything on here?????

Answer 24

of the step by steps

Answer 25

for finding everything

Answer 26

please i am not trying to miss anything

Answer 27

hello?

Answer 28

that is the whole thing yes???

Answer 29

@HossamHoussien