已知一个三角形的两边长为3和4，若第三边长是方程x2-12x+35=0_爱下问搜题

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问题填空题

已知一个三角形的两边长为3和4，若第三边长是方程x²-12x+35=0的一个根，则这个三角形周长为（），面积为（）。

答案

7；6

选择题

标有“2V 1W”字样的小灯泡和标有“20 1A”字样的滑动变阻器，连接在如图所示的电路中。已知电源电压为6V，电流表的量程为“0—0.6A”，电压表的量程为“0—3V”。闭合开关，移动滑动变阻器滑片，电流表、电压表示数的变化范围是

A．0.25A—0.5A 1V—2V

B．0.25A—0.6A 1V—2V

C．0.3A—0.5A lV—1.5V

D．0.25A—0.5A 1.5V—2V

单项选择题

Passage One

It is quite reasonable to blame traffic jams, the cost of" gas and the great speed of modern life, but manners on the toad are becoming horrible. Eye,body knows that the nicest men would become fierce tigers behind the wheel. It is all right to have a tiger in a cage, but to have one in the driver’s seat is another matter.
Road politeness is not only good manners, but good sense too. It takes the most cool-headed drivers great patience to give up the desire to beat back when forced to face rude driving. On the other hand, a little politeness goes a long way towards reducing the possibility of quarrelling and fighting. A friendly nod or a wave of thanks in answer to an act of politeness helps to create an atmosphere of good will and calmness so necessary in modern traffic conditions. But such behaviors of politeness are by no means enough. Many drivers nowadays don’t even seem able to recognize politeness when they see it.
However, misplaced politeness can also be dangerous. Typical examples are the driver who waves a child crossing the street at a wrong place into the path of oncoming cars that may be not able to stop in time. The same goes for encouraging old ladies to cross the road wherever and whenever they want to.
An experienced driver, whose manners are faultless, told me it would help if drivers learnt to correctly join in traffic stream without causing total blockages that give rise to unpleasant feelings. Unfortunately, modern drivers can’t even learn to drive,let alone master the roadmanship. Years ago, experts warned us that the fast increase of the car ownership would demand more give-and-take from all road users. It is high time for all of us to take this message to heart.

It is not always right for drivers to______.

A．master roadmanship

B．recognize politeness when they see it

C．encourage old ladies to cross the road whenever and wherever they want

D．give a friendly nod in answer to an act of politeness