  Let $X$ be a proper smooth variety having an affine open subset defined by
the normic equation $N_{k(\sqrt{a},\sqrt{b})/k}({x})=Q(t_{1},...,t_{m})^{2}$
over a number field $k$. We prove that : (1) the failure of the local-global
principle for zero-cycles is controlled by the Brauer group of $X$; (2) the
analogue for rational points is also valid assuming Schinzel's hypothesis.
