find eqn of tangent line to y = 1/x^2 at the point (-1, 1)

[withay]

I don't quite understand how to do this problem... It states:

Find the equation of the tangent line given the curve and through the given point on the curve. Please put your equation in slope intercept form.

y= 1/xsquared with the point (-1,1)

Everytime I attempt to solve the problem I end up getting a zero at the bottom and not being able to find the slope with the little formula that one uses to find it...(it's really long)...please help, I would appreciate it so much!

 

[pka]

\(\displaystyle y = \frac{1}{{x^2 }}\quad \Rightarrow \quad y' = \frac{{ - 2}}{{x^3 }}\)