则方程
的根的个数为( )\n \n \n \n \n \n \n \n \n \n \n A.\n 0\n
\n \n\n \n \n \n B.\n 1\n
\n \n\n \n \n \n C.\n 2\n
\n \n\n \n \n \n D.\n 3\n