18. Quadratic function often appears in the form of the final question in the senior high school entrance examination, which often accounts for 18. This paper mainly investigates how the general formula in the quadratic resolution function becomes the vertex through the formula, and then works out the vertex coordinates and symmetry axis, draws the image of the quadratic function, and works out the intersection coordinates of the quadratic function with the X-axis and the Y-axis and the opening direction of the parabola.