抛物线y=-x2-2x+m,若其顶点在x轴上,则m=_.

问题描述:

抛物线y=-x2-2x+m,若其顶点在x轴上,则m=______.

∵抛物线y=-x2-2x+m,若其顶点在x轴上,

4×(−1)×m−(−2)2
4×(−1)
=0,解得m=-1.
故答案为:-1.