Answer:
Simplifying
an = 8n + -7
Reorder the terms:
an = -7 + 8n
Solving
an = -7 + 8n
Solving for variable 'a'.
Move all terms containing a to the left, all other terms to the right.
Divide each side by 'n'.
a = -7n-1 + 8
Simplifying
a = -7n-1 + 8
Reorder the terms:
a = 8 + -7n-1