题干

关于x的方程x2-mx-1=0根的情况是(    )

A:有两个不相等的实数根

B:有两个相等的实数根

C:没有实数根

D:不能确定

上一题 下一题 0.0难度 选择题 更新时间:2016-01-04 06:14:43

答案(点此获取答案解析)

A

同类题2

阅读理解

    Last April, on a Sunday, we took one of our “nowhere” drives. My husband was quietly driving along a back road. I was occupied in the front passenger seat watching the scenery.

    I noticed out of the corner of my eye that my husband was struggling to look out of my window. This frightened me, since his eyes should be on the road in front of him. I asked him what he was looking at out of the windows, and he quietly replied, “Nothing.”

    After a few minutes, I looked over at my husband and noticed a tear running down his cheek. I asked him what was wrong. This time he told me, “I was just thinking about Pop and a story he had once told me.” It had something to do with Pop, his friend from childhood, and I wanted to know the story, so I asked him to share it with me.

    He said, “When I was 8 years old, Pop and I were out fishing and he told me that the pine trees know when it is Easter.”

    I have no idea what he meant by that, so I pressed him for more information.

    He continued on… “The pine trees start their new growth in the weeks before Easter because spring is drawing near. If you look at the tops of the pine trees, you will see the yellow shoots. As the days get closer to Easter Sunday, the tallest shoot will branch off and form a cross. By the time Easter Sunday comes around, you will see that most of the pine trees will have small yellow crosses on all of the tallest shoots.”

    I turned to look out of the window and I couldn't believe my eyes. It was a week before Easter, and you could see all of the trees with the tall yellow shoots stretching to the sky.

    The tallest ones shone in the sunlight like rows of tiny golden crosses. May you find your Easter season filled with beautiful golden crosses!

同类题4

在19世纪下半叶的世界舞台上,有三个国家异曲同工地演绎了自己的精彩。阅读材料,回答下列问题。

材料一:一个农奴的反映:3月5日,一个伟大的日子。解放宣言!我在中午前后拿到了一份。阅读这份珍贵法案时,我无法表达自己的喜悦。在俄罗斯几千年的历史中,很少有文件能和它相媲美。……我无法呆在家里,我要到街上走走。人们在这里或那里大声读着声明。我不断听到诸如“自由法令”和“自由”等词汇。──摘编自《全球视野下的西方文明史》

材料二:俄国19世纪60年代初和90年代初的统计数据表

年份

棉花加工(吨)

冶铁(吨)

1861年

30951

327610

1891年

171994

992210

材料三:在短短的几十年里,日本就按自己的节奏改变了自身。以前它是个前工业时代的封建社会,到19世纪末期,新日本──西方影响和日本传统的混合物──成为一个正在上升的帝国。它很快将成为西方一个可怕的竞争对手。──《全球视野下的西方文明史》

材料四:宣言声明:南方的奴隶将得到解放,一旦北方联邦军队进入叛乱区,就解除他们的奴隶枷锁。于是,他将这场内战变成了一场解放奴隶的战争,从而得到了许多政治和军事上的优势。北方人的士气更加高涨,南方人的继续顽抗似乎已经是徒劳无益的了。这一宣言鼓励大批奴隶离开他们南方的主人,开创了北方军队征集黑人新兵的新局面。