Answers

2015-03-14T12:25:05+05:30
X3=1
first term=f
common difference=d
f+2d=x3
f+2d=1...(1)

x6=f+5d
-11=f+5d
f+5d= -11 ...(2)

(1)-(2)

f+2d=1-
f+5d= -11
---------------
12=-3d
d= 12/-3= -4
f+2d= -1
f-8=-1
f=7

sn= \frac{n}{2}[2f+(n-1)d] \\  \\ 
 \frac{32}{2}[-14+ 31*-4) \\  \\ 
16(-14-124) \\  \\ 
16(-138)  
=−2208


1 5 1
THE ANSWER IS WRONG THE ANSWER SHOULD BE -1856
Comment has been deleted
2015-03-14T14:15:29+05:30

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