问题
选择题
抛物线y=x2-2x-3的顶点坐标是( )
A.(-1,-4)
B.(3,0)
C.(2,-3)
D.(1,-4)
答案
∵y=x2-2x-3
=x2-2x+1-4
=(x-1)2-4,
故顶点的坐标是(1,-4).
故选D.
抛物线y=x2-2x-3的顶点坐标是( )
A.(-1,-4)
B.(3,0)
C.(2,-3)
D.(1,-4)
∵y=x2-2x-3
=x2-2x+1-4
=(x-1)2-4,
故顶点的坐标是(1,-4).
故选D.