The given expression can be rewritten as;

If we expand the above equation, we'll still have the same expression in the question.
We can now factorize, which will give us;

We apply the difference of two squares , we'll then have;

So, we'll then have the below as factors;

The roots of the polynomial then will be 1, -1, -1/2 which we'll get from equating each factor to zero and solving for x.