Finding the equations of the tangent to the curve at the given point.

$\displaystyle y = 4/x^2 at$ x = 1

I understand how to work out this but I haven't figured out how to treat fractions. For example I can workout $\displaystyle y = 5x^2 + 3$.

Please help as this for a test and I need to figure out how to work it out.

Thanks.