Answers

2014-01-13T17:09:08+05:30
Tn=a+(n-1)d
so     7n=a+(n-1)d
now T1=7*1=7
        T2=14
        T3=21
so  Tn-T(n-1)=7n-7(n-1)
                     =7n-7n+7
s0 difference D=7
so Tn is A.P
7,14,21,28,35,42,49,...............................
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