点P(5,-8)关于x轴的对称点在( )
A:第一象限
B:第二象限
C:第三象限
D:第四象限
— Could you tell me ___________?
— Sorry, I don't know. I will call you when he comes back.
如图,某涵洞的截面是抛物线形,现测得水面宽AB=1.6m,涵洞顶点O到水面的距离CO为2.4m,在图中直角坐标系内,涵洞截面所在抛物线的解析式是____
____
读图,回答下列问题: