Math, asked by vishalsaini1802, 11 months ago

7th term of an AP is 40 then the sum of first thritten term is

Answers

Answered by jay335499
3

Answer:

t7=40

a+6d=40

s13=13/2×2a+12d

s13=13/2×2(a+6d)

s13=13×40

s13=520

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