Note that "Jewishness" has the meanings both of "adherence to the religion of Judaism" and "membership in the ethnic group 'Jews'". People of both groups are listed here.
... x) to the expression to the left of "=", that will make it a perfect square trinomial of the form x2 + 2xy + y2. Since "2xy" in this case is (b/a)x, we must have y = ...