若A+（3x²-y²）=4x²-xy+y²,则A等于?（A）7x²+xy+2y²（B）x²+xy+2y²（C）7x²-xy+2y²（D）x²-xy+2y²

x��)�{ѽ�Q���� 5eCsk�J�~O�� L��R*��c���Ov��u9��CUiU�uw8
���8#i�E�rAhB��I*ҧĥ`�x����f�4.���q�^���f(�����IE��1qF��� �i6r�J]l���~�
s�|��颠�tC��e;�I q�d