1, know the meaning of | a | (where a stands for rational number)

2. Know the concepts of the simplest quadratic root and the simplest fraction.

3. Simple algebraic expression multiplication can be performed by adding linear multiplication and quadratic multiplication.

4. The discriminant of the roots of a quadratic equation will be used to judge whether the equation has real roots and whether the two real roots are equal.

5. The analytical expression of linear function will be determined by the coefficient method of undetermined coefficient.

6.* Understand the relationship between the roots and coefficients of a quadratic equation.

7, * can solve simple ternary linear equations,

8.* Knowing the coordinates of three points on a given line, we can determine a quadratic function.

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1, which can reasonably explain and infer information containing large numbers.

2. Understand the concept of significant digits.

3. According to the quantitative relationship in specific problems, a group of linear inequalities can be listed to solve simple problems.

4. The limit of "there are no letters in the absolute value symbol" when finding the absolute value.