Hi! Okay, I have this fraction. The instructions specifically say "simplify for all values of a for which the expression is defined", which I'm guessing is a fancy way of asking you to reduce it:

$\displaystyle \frac{1-\frac{2}{a}}{\frac{4}{a^2}-1}$

I multiplied top and bottom by $\displaystyle a^2$ and got this:

$\displaystyle \frac{a^2-2a}{4 - a^2}$

I'm really stuck now. Any help is very much appreciated! Thank you!