Step-by-step explanation:
The formula for Arithmatic Series is
[tex]a_n=a_1+(n-1)d[/tex]
where a_1 and a_n are the first and n-th term of the series respectively,
d is the common difference of the series.
Now,
The eigth term is given by,
[tex]a_8=(\frac{d}2)+(8-1)d=\frac{15}{2}d[/tex]
