Question

in an ap the common difference d and 7th term is 4 then find the 1st term

Answer 1

4=a+(n-1)d
a=?
4=a+(7-1)4
a=4-24
=-20

Answer 2

d=4
7th term=4
a7=a+6d
4=a+6×4
4=a+24
a=-20