Junior high school theoretical knowledge involves real numbers, radical related concept operations (radical simplification and deformation), power operations, power concepts and absolute value operations, which need to be understood and consolidated. The basic requirement is to be as familiar with the operation as possible.
Quadratic equation of one variable, the key point in the key point! ! ! ! ! ! ! ! ! !
(1) The most practical method for finding roots: factorization (also called cross multiplication),
Formula method (you should know that it is derived by matching "complete square", and if you understand it, you will know "why △ can't be less than 0")
(2) Regarding cross multiplication and Vieta theorem, if you don't master this, don't study high school mathematics.
Images and analytical expressions of univariate quadratic function (this is more complicated for students, and you will be familiar with it by looking at the picture table)
Let's not talk about anything else. Nothing interesting.