y=3x²-6x,求开口方向,顶点坐标,对称轴

y=3x²-6x,求开口方向,顶点坐标,对称轴

y=3x²-6x
=3(x²-2x+1-1)
=3(x²-2x+1)-3
=3(x-1)²-3
开口向上,顶点坐标为（1,-3）,对称轴为 x=1