Which is the value of this expression when 0=-2 and 4 =-1?

Can someone answer this question for me

Astudent solves the equation for v. start with the original equation. use the square root property. use the division property of equality. use the multiplication property of equality. simplify. which statement explains how to correct the error that was made? the square root property must be applied after all other properties of equality are applied. the multiplication property of equality should have been applied before the division property of equality. the division property of equality should have been applied to move the fraction to the other side of the equation. the square root property should have been applied to both complete sides of the equation instead of to select variables.

What is the 8th term of the geometric sequence with this explicit formula? an= )(n-1)