Let the quadratic resolution function y=ax2+bx+c, and substitute it into the above three coordinates to get a+b+c=3, c=4, a-b+c= 1, and just solve this equation group.
2. Vertex: The coordinate of the vertex of the quadratic function is (-2,3) and the analytical formula (-1, 1) is obtained through this point.
Let the quadratic resolution function y=a(x+2)2+k and substitute it into (-1, 1) to find a.
3. Binomial formula: The quadratic function is solved by (0, -3)(0, 4)(-4, 2).
Let the quadratic resolution function y=a(x+3)(x-4) be substituted into (-4,2) to find a.
Generally, mastering these three methods is enough. I wonder if it will help you. Work hard!