Find the more formulas you learn in junior high school, the better

1. The nature of non-negative numbers: absolute values.

The absolute value of any number is non-negative, and when the absolute values of several numbers or formulas add up to 0, each of them must be equal to 0

According to the above properties, the equation can be listed to find the value of the unknown

2. The nature of non-negative numbers: even power.

Even power is non-negativity

The even power of any number is a non-negative number, and when the sum of the even powers of several numbers or formulas is 0, each of them must be equal to 0

3. Mixed operations of rational numbers.

1) The mixed operation order of rational numbers: first calculate the multiplication, then multiplication and division, and finally add and subtract; Sibling operations should be calculated in order from left to right; If there are parentheses, do the bracket calculations first

2) When performing mixed operations on rational numbers, pay attention to the application of each operation law to simplify the operation process

Regular Method] Four Operational Techniques for Mixed Operations on Rational Numbers.

1 Transformation method: one is to convert division into multiplication, the other is to convert the power into multiplication, and the third is to convert decimals into fractions for reduction calculation in the mixed operation of multiplication and division in the pure town

2. Integer method: In the mixed operation of addition and subtraction, two numbers with a sum of zero, two numbers with the same denominator, two numbers with an integer, and two numbers with a product of an integer are usually combined into a group to solve

3 Splitting method: Split the fraction into the form of an integer and the sum of a true fraction, and then calculate

4 Clever use of arithmetic: Clever use of addition or multiplication in calculations often makes calculations easier

4. Algebraic Evaluation:

If the value of the algebraic formula can be simplified, it should be simplified first and then evaluated

The question types are briefly summarized in the following three types:

The known conditions are not simplified, and the split coarse is algebraically simplified;

Known conditions are simplified, and the given algebraic formulas are not simplified;

Both the known conditions and the given algebraic equations are to be simplified

5. Similar items.

1) Definition: The same letter is contained, and the index of the same letter is also the same, such an item is called a similar term

The letters contained in the same kind of terms can be seen as numbers, mononomials, polynomials, and so on

2) Precautions:

One is that the letters contained are the same, and the other is that the index of the same letter is also the same, and both are indispensable;

The homogeneity term is independent of the size of the coefficient;

Homogeneous items are not related to the alphabetical order they contain;

All constant terms are homogeneous

In parallel, the slope k is the same, but b is different.

So y=kx+c(c≠b).

Two parallel lines mean that k is the same, and the two lines do not coincide, so we can let y=kx+c (c is not equal to b).