<PRE><B>Question 858285</B>
Find the first term of an A.p if the 5th term is 28 and sum of the first 17th term is Zero

tn = a+(n-1)d

28 = a+4d

a+4d= 28....................(1)

Sn = n/2( 2a+(n-1)d))

0= (17/2)(2a+16d)

0= 17(2a+16d)

34a+272d=0
/34
a+8d=0.....................(2)

subtract (2) from (1)

we get -4d=28
d= -7

Now a+4d=28

a+4*(-7)=28

a-28=28
a=56





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