In order to "exclude" possible negative $x$ we can do the trick of taking the square root, since this is not possible for negative numbers, then cancel the square root by using a square. Thus the equation will be identical as the one above, but only defined on the positive numbers for $x$.
$$(\sqrt x^2)^2 - y^2 = 1$$
Note that we could in a similar way get only the "left" part of the curve, with negative $x$ values, by putting a minus sign on $x$, i.e.
$$(\sqrt{ -x}^2)^2 - y^2 = 1$$