Several analytic expressions of mathematical quadratic function What general form, vertex form and so on. Be clear

Several analytic expressions of mathematical quadratic function What general form, vertex form and so on. Be clear

The quadratic function can be expressed as f (x) = ax ^ 2 + BX + C (a is not 0). Its image is a parabola whose principal axis is parallel to y axis
In general, the relationship between independent variable x and dependent variable y is as follows:
General formula: 1: y = ax ^ 2; + BX + C (a ≠ 0, a, B, C are constants), then y is called the quadratic function of X
Number. Vertex coordinates (- B / 2a, (4ac-b ^ 2) / 4A)
2: Vertex formula: y = a (X-H) ^ 2 + K or y = a (x + m) ^ 2 + K (the two formulas are essentially the same,
But it's the first formula in junior high school textbooks.)
3: Intersection (and X-axis): y = a (x-x1) (x-x2)