f (x) = x2 - 4/ x2 - 1

Question

This needs to be plotted onto a graph, but I don't know how

Answer 1

I am sure you mean

f(x) = (x^2 - 4)/(x^2 - 1)

make a table of values, picking any value x you want, except x =±2 or x =±1
plot the points, until you see the outline of the curve

or

you could use this webpage
http://rechneronline.de/function-graphs/
enter (x^2 - 4)/(x^2 - 1) where it says "1st graph"
and adjust the "ranges" if you have to