if nth term of an A.P is 4, common difference is 2 and sum of n terms is -14 then find first term and the number of terms
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Answer:
an=4
d=2
sn=-14
an=a+(n-1)d
4=a+2n-2
6-2n=a_____(1)
sn=n/2[a+(n-1)d]
-14=n/2(6-2n+2n-2]
-14=n/2(4)
-14=2n
n=-7
now put these value in eq^n__(1)
6-2(-7)=a
a=20
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