挑战习题
1/5单选题
难度:

1.

二次函数y=ax2+bx+c的图象如图所示,图象在x轴的下方部分,x的取值范围为(  )


A

x<-1或x>3

B

-1<x<3

C

x≤-1或x≥3

D

-1≤x≤3

提示1:
PHA+5ZyoeOi9tOS4i+aWue+8jOWwseaYr+aJvnkmbHQ7MOeahOWbvuWDj++8jOWvueW6lHjnmoTojIPlm7Q8L3A+
正确答案:Qg==
PGRpdj48cD48YnI+PC9wPjxwPuino++8muKIteWbvuixoeWcqHjovbTnmoTkuIvmlrnpg6jliIbvvIw8YnI+4oi0eOeahOWPluWAvOiMg+WbtOS4ui0x77yceO+8nDPvvI48YnI+5pWF6YCJQjwvcD48L2Rpdj4=