Find the sum of following A.P(I)2,7,12,...........,to 10 terms

1.	Find the sum of following A.P(I)2,7,12,...........,to 10 terms
Answer» Thanks a=2,,,,,,,,,,,, d=5 ..................................... l=a+(n-1) d ====....... 2+(10-1) 5======= .. 2+9×5====....2+45=47 .,...................................... Sn=n/2×(a+l) ====10/2[2+47]========549=====245 Common difference =7-2=5First term(a)=2An=10S=n/2[2a+(n-1)dS=10/2{2(2)+(10- 1)5S=5{4+9(5)}S=5{4+45}S=5(49)S=245 a=2 d =5 n=10Sn=?Sn=n/2 [2a+(n-1)d]Sn=10/2[22+(10-1)5)]Sn=5[4+95]Sn=5[4+45]Sn=5[49]Sn=245.

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