(9)设A是3阶实对称矩阵, =((-1,1,1))^T 满足 (A-2E)a=0, 且 (A)=1, k1,k2-|||-为任意常数,则方程组 Ax=0 的通解为 ()-|||-A. _(1)((1,1,0))^T+(k)_(2)((1,-1,0))^r. B. _(1)((1,1,0))^T+(k)_(2)((1,0,1))^T.-|||-C. _(1)((1,1,0))^T+(k)_(2)((1,1,1))^T. D. _(1)((1,1,0))^T+(k)_(2)((1,0,-1))^T.