挑战习题
1
/5
单选题
难度：
1.二次函数y=kx
2
-6x+3的图象与x轴有交点，则k的取值范围是（ ）
A
k＜3
B
k＜3且k≠0
C
k≤3
D
k≤3且k≠0
提示1：
5Yip55Soa3g8c3VwPjI8L3N1cD4tNngrMz0w5pyJ5a6e5pWw5qC577yM5qC55o2u5Yik5Yir5byP5Y+v5rGC5Ye6a+WPluWAvOiMg+WbtO+8jg==
正确答案：
RA==
6Kej77ya4oi15LqM5qyh5Ye95pWweT1reDxzdXA+Mjwvc3VwPi02eCsz55qE5Zu+6LGh5LiOeOi9tOacieS6pOeCue+8jDxicj7iiLTmlrnnqItreDxzdXA+Mjwvc3VwPi02eCszPTDvvIhr4omgMO+8ieacieWunuaVsOague+8jDxicj7ljbPilrM9MzYtMTJr4omlMO+8jGviiaQz77yM55Sx5LqO5piv5LqM5qyh5Ye95pWw77yM5pWFa+KJoDDvvIzliJlr55qE5Y+W5YC86IyD5Zu05piva+KJpDPkuJRr4omgMO+8jjxicj7mlYXpgIlE77yO
2
/5
单选题
难度：
2.关于x的一元二次方程x
2
-x-n=0没有实数根，则抛物线y=x
2
-x-n的顶点在（ ）
A
第一象限
B
第二象限
C
第三象限
D
第四象限
提示1：
5rGC5Ye65oqb54mp57q/eT14PHN1cD4yPC9zdXA+LXgtbueahOWvueensOi9tHg9PGltZyB3aWR0aD03IGhlaWdodD00MiBzcmM9Imh0dHBzOi8vcDEucWluZ2d1by5jb20vRzEvTTAwLzgxL0YyL3JCQUNKbFYwOXdHaUlIV1BBQUFCSkh2OVRiQTAwMS5wbmciPu+8jOWPr+efpemhtueCueWcqHnovbTnmoTlj7Pkvqc=
提示2：
5qC55o2ueDxzdXA+Mjwvc3VwPi14LW49MOWcqOWunuaVsOiMg+WbtOWGheayoeacieWunuaVsOague+8jOWPr+efpeW8gOWPo+WQkeS4iueahHk9eDxzdXA+Mjwvc3VwPi14LW7kuI546L205rKh5pyJ5Lqk54K577yM5o2u5q2k5Y2z5Y+v5Yik5pat5oqb54mp57q/5Zyo56ys5LiA6LGh6ZmQ77yO
正确答案：
QQ==
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
3
/5
单选题
难度：
3.已知抛物线y=x
2
-2x+1与x轴的一个交点为（m，0），则代数式m
2
-2m+2013的值为（ ）
A
2011
B
2012
C
2013
D
2014
提示1：
5qC55o2u5Zu+6LGh5LiK54K555qE5Z2Q5qCH5oCn6LSo5b6X5Ye6bTxzdXA+Mjwvc3VwPi0ybT0tMe+8jOi/m+iAjOS7o+WFpeaxguWHuuWNs+WPr++8jg==
正确答案：
Qg==
6Kej77ya4oi15oqb54mp57q/eT14PHN1cD4yPC9zdXA+LTJ4KzHkuI546L2055qE5LiA5Liq5Lqk54K55Li677yIbe+8jDDvvInvvIw8YnI+4oi0bTxzdXA+Mjwvc3VwPi0ybSsxPTDvvIw8YnI+4oi0bTxzdXA+Mjwvc3VwPi0ybT0tMe+8jDxicj7liJnku6PmlbDlvI9tPHN1cD4yPC9zdXA+LTJtKzIwMTM9LTErMjAxMz0yMDEy77yOPGJyPuaVhemAie+8mkI=
4
/5
单选题
难度：
4.若抛物线y=x
2
-2x+m与x轴有两个交点，则m的取值范围是（ ）
A
m＜-1
B
m＜1
C
m＞-1
D
m＞1
提示1：
55u05o6l5Yip55So5oqb54mp57q/5LiOeOi9tOS6pOeCueS4quaVsOS4juKWs+eahOWFs+ezu+axguWHuuWNs+WPr++8jg==
正确答案：
Qg==
6Kej77ya4oi15oqb54mp57q/eT14PHN1cD4yPC9zdXA+LTJ4K23kuI546L205pyJ5Lik5Liq5Lqk54K577yMPGJyPuKItGI8c3VwPjI8L3N1cD4tNGFjPTQtNG3vvJ4w77yMPGJyPuino+W+l++8mm3vvJwx77yOPGJyPuaVhemAie+8mkLvvI4=
5
/5
单选题
难度：
5.已知二次函数y=x
2
+2x-10，小明利用计算器列出了下表：
x
-4.1
-4.2
-4.3
-4.4
x
2
+2x-10
-1.39
-0.76
-0.11
0.56
那么方程x
2
+2x-10=0的一个近似根是（ ）
A
-4.1
B
-4.2
C
-4.3
D
-4.4
提示1：
55yLMOWcqOebuOWvueW6lOeahOWTquS4pOS4qnnnmoTlgLzkuYvpl7TvvIzpgqPkuYjov5HkvLzmoLnlsLHlnKjov5nkuKTkuKp55a+55bqU55qEeOeahOWAvOS5i+mXtO+8jg==
正确答案：
Qw==
6Kej77ya5qC55o2u6KGo5qC85b6X77yM5b2TLTQuNO+8nHjvvJwtNC4z5pe277yMLTAuMTHvvJx577ycMC41Nu+8jOWNsy0wLjEx77yceDxzdXA+Mjwvc3VwPisyeC0xMO+8nDAuNTbvvIw8YnI+4oi1MOi3nS0wLjEx6L+R5LiA5Lqb77yMPGJyPuKItOaWueeoi3g8c3VwPjI8L3N1cD4rMngtMTA9MOeahOS4gOS4qui/keS8vOagueaYry00LjPvvIw8YnI+5pWF6YCJQ++8jg==