(n^2-1)/(2n²-7n-4) excluded value?
The only "excluded" values are those that make the denominator = 0
So we have
2n^2 - 7n - 4 = 0 factor
(2n +1)(n - 4) = 0 and setting both factors to 0, we find that the "excluded" values are n = -1/2 and n = 4