The standard form is Y = AX+BX+C. As long as you know any three points in the evaluation, you can get the analytical expression of the ternary linear equations, which is relatively simple, and no examples are given here.

The second method is called vertex, and the standard form is y = a (x-h) 2+c, which is used when one vertex and another point are known.

For example, if the vertex of a quadratic function is (3,5) and passes through (4,0), find its analytical expression.

Solution: Let the relationship of this function be y = a (x-h) 2+c, vertex (3,5) and intersection (4,0), then h = 3, c = 5, substitute x = 4 and y = 0 to get the value of a, and then we can get its analytical formula.

Note: If you still don't understand, you can adopt the following methods: Because the vertex (3,5) of the function and the symmetry axis of the function are x = 3, then the function must pass through the symmetry point (2,0) of (4,0), so there are three points, which can be solved by the general formula.

The third method is called intersection method, and the standard form is y = a (x+m) (x+n). Used when there are two intersections and another point between the function and the x axis in the topic. For example, a quadratic function can be solved by (4,0), (-1 0), and (0,3).

Solution: Let the relation of this function be y = a (x+m) (x+n) on (4,0), (-1, 0) and (0,3). When x = 4 and y is 0, there must be one of (x+m) or (x+n).

Note: the general formula can be used at the intersection, but it is more troublesome.