For this case we have:
The arithmetic sequence formula is given by:
[tex]a_n = a_1 + (n-1) * d[/tex]
Where:
a_n: It's the last term
a_1: It's the first term
n: Position of the term
d: Common difference
We want to find [tex]a_8[/tex]:
[tex]a_8 = a_1 + (8-1) * d[/tex]
Substituting the values of a_1 and d
[tex]a_8 = -7 + (7) (0.5)[/tex]
[tex]a_8 = -7 + 3.5a_8 = -3.5[/tex]
Answer:
[tex]a_8 = -3.5[/tex]