Question

Given a=7a13=35 find d and s13​

Answer 1

Answer:

d=7/3 and s13=273

Step-by-step explanation:

35=7+(13-1)d

35-7=12d

28=12d

d=28/12

d=7/3

s13=13/2[2×7+(13-1)7/3]

= 13/2[14+28]

= 13/2×42

=13×21

= 273

hope it helps you