题目7.若曲面 =xy 在点M处的法线垂直于平面-|||-2x+3y+z-8=0 则点M的坐标为()-|||-A (-3,-2,6)-|||-__-|||-B (-2,3,-6)-|||-C (2,3,6)-|||-__-|||-D (-2,-3,6)题目解答答案