In order to solve your problem, let's use the Compount Interest Equation:

P = C*(1 + r/n)^(nt)

Let me just give a quick overview of the variables in this equation and what they mean.

The variable n is used to define the frequency of which the interest is compounded.  Usually, interest is compounded yearly, but in this case, the interest is compounded monthly.  So n = 12.

The variable P is the variable we are looking for.  That is the future interest collected.

The variable C is the initial account, which in this case is $700.

The variable r is the rate of interest, which in this case is 8%, or .08

The variable t is how many years the investment continues, which in this case is t = 9 years.

So now let's plug into the equation and solve for P:

P = $700*(1 + .08/12)^(12*9)

P = $700*(1 + .00666)^(108)

P = $1434