Question

find the sum of 7+10+1/2+14+............+84

Answer 1

a=7
l=84
n=?
d=10-7
=3
to find n=(l-a÷d)+1
after finding the n find the sum using


Sn=n/2 (2a+(n-1)d)


with using these formulae find ur answer

Answer 2

Answer:

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