Here is my working out:

let n^2 - 3 = 4m

By way of contradiction assume n^2 - 3 is rational, ie; n^2 - 3 = a/b (BTW in the funky looking expression for n the square root sign is not supposed to be over the 1/sqrt(p))

Once again by way of contradiction, assume sqrt(p) is rational:

Any help would be appreciated