Question

in an A.P , given a=7,a13,=35,find d and S13​

Answer 1

Step-by-step explanation:

i don't medam i will try.....

Answer 2

Answer:

d=7/3,S13=273

Step-by-step explanation:

for a nth term

a n=a+(n-1)d

for Sn ,

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