顶乎喊点式:y=a(x-k)²+h交点式:y=a(x-x1)(x-x2)顶点坐标:∵y=ax²+bx+c =a(x²岁手野+(b/a)x)+c =a[x²+2×(b/2a)x+(b/2a)²-(b/2a)²]+c=a(x+a/2b)²+(4ac-b²)/4a ∴顶点坐标:(薯早-b/2a,(4ac-b²)/4a)
牢州磨樱记册丛游握