满分5 >
初中数学试题 >
(2008•铜仁地区)设一元二次方程x2+bx+c=0的两根为x1,x2,则两根...
(2008•铜仁地区)设一元二次方程x
2+bx+c=0的两根为x
1,x
2,则两根与方程之间有如下的关系:x
1+x
2=
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/201310201203347622544425/SYS201310201203347622544017_ST/0.png)
,x
1x
2=
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/201310201203347622544425/SYS201310201203347622544017_ST/1.png)
.请根据这种关系填空:已知x
1,x
2是2x
2+5x+4=0的两个实数根,则
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/201310201203347622544425/SYS201310201203347622544017_ST/2.png)
=
.
考点分析:
相关试题推荐
(2008•铜仁地区)已知⊙O
1和⊙O
2内切,且圆心距为10cm,若⊙O
1的半径为3cm,则⊙O
2的半径为
cm.
查看答案
(2008•铜仁地区)有一副扑克牌,共52张(不包括大王、小王),其中四种花色:红桃,梅花,方块,黑桃各有13张,把扑克牌充分洗匀后,随意抽取一张,则抽得“红桃”的概率是
.
查看答案
(2008•铜仁地区)数学组活动,老师带领学生去测塔高,如图,从B点测得塔顶A的仰角为60°,测得塔基D的仰角为45°,已知塔基高出测量仪20m,(即DC=20m),则塔身AD的高为
米.
查看答案
(2008•铜仁地区)观察如下等式:
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/201310201203347622544425/SYS201310201203347622544013_ST/0.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/201310201203347622544425/SYS201310201203347622544013_ST/1.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/201310201203347622544425/SYS201310201203347622544013_ST/2.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/201310201203347622544425/SYS201310201203347622544013_ST/3.png)
,根据以上规律,得出
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/201310201203347622544425/SYS201310201203347622544013_ST/4.png)
=
.
查看答案
(2008•铜仁地区)在△ABC中,已知两条边a=6,b=7,则第三条边c的取值范围是
.
查看答案