With the union method, there are steps to factor each of the following numbers

1. Polynomials.

Divide by polynomials is generally calculated vertically, the divided formula and the division formula are arranged by a certain letter as a decreasing power, and the missing term is filled with zero, the first term of the divided formula is divided by the first term of the division formula to get the first term of the quotient formula, the first term of the quotient formula is used to multiply and divide, the product is written below the divided formula (aligned with similar terms), the equal terms are eliminated, the unequal terms are combined, the difference obtained is taken as a new divided, and then the calculation is continued according to the above method until the colossal is zero or the number of the covariance is less than the number of divisions, Divided = Divided Quotient + Remainder. If the remainder is zero, the polynomial is divisible by another polynomial.

2. Convert a polynomial into several rounded formulas in a range (such as decomposition in the range of real numbers, that is, all terms are real numbers).

The product of the form, this sub-deformation is called the factorization of this polynomial.

It's also called factoring the polynomial.

There's no chance that your C is wrong.

If C is not written wrong, there is no answer, which can be proven:

a.-a -b =-(a +b) If this can be decomposed, b can also be decomposed and then c, without the quadratic term of b, it is impossible to decompose.

D term, even if it can be decomposed, it is not an acceptable answer: it can be decomposed into 25(m-(-15+(675) imaginary numbers are out...

In the following polynomials, the formula formula can be used to decompose the factors are (c) squared - xy squared + xy squared - y squared + y squared (2), and the following equations are perfectly squared, and the formula (a) is perfectly squared

The square of -x + a quarter of the square of the square + 2x-17 e5

Answer C Question Analysis: According to the complete square formula and the structural characteristics of the square square square method is used to analyze and judge each option and then use the elimination method

a. x2xy can extract the common factor x, and the formula method cannot be used to decompose the factor, so this option is wrong;

b. x2 "Regret Feng Gao sup> xy can extract the common factor x, and cannot use the formula method to decompose the factor, so this option is wrong;

c、x2－y2

It conforms to the structural characteristics of the squared difference formula, and can use the formula method to decompose the factor, so this option is correct;

d、x2y2

It does not conform to the structural characteristics of the squared difference formula and the perfect squared formula, and the formula method cannot be used to decompose the factor, so this option is wrong

Therefore, choose C test point: This question examines the formula method to decompose the factor.

Comments: Memorizing the structural characteristics of the perfect square formula and the square difference formula is the key to solving the problem View the original post

If a polynomial has a common factor, the common factor should generally be extracted first;

If there is no common factor for each item of a polynomial, we should generally think about using formulas and cross multiplication; If there are two terms of the polynomial, the formula of square difference should be considered, and if the polynomial has three terms, the formula method or cross multiplication method should be considered; If the polynomial is more than three, consider using the group decomposition method;

When factoring a factor, it must be factored to the point where it can no longer be factored

Common methods for factoring a polynomial include the common factor method and the formula method.

Mention the common factor method.

The common factors that are contained in the terms of several polynomials are called the common factors of the terms of the polynomial. If the items of a polynomial have a common factor, you can propose this common factor to reduce the polynomial into the form of the product of two factors, and this method of factoring is called the common factor method.

Specific method: when all coefficients are integers, the coefficients of the common factor should be taken as the greatest common divisor of each coefficient; The letters are the same letters, and the index of each letter is the lowest number; Take the same polynomial, and the number of polynomials is the lowest. If the first term of the polynomial is negative, it is common to put a "-" sign so that the coefficient of the first term in parentheses becomes positive.

When the "-" sign is proposed, each item of the polynomial must be changed.

If the formula method reverses the multiplication formula, you can factor some polynomials, which is called the formula method.

Square Difference Formula:

Perfect Square Formula:

Note: A polynomial that can be factored using a perfectly squared formula must be trinomial, two of which can be written as the sum of the squares of two numbers (or equations) and the other as twice the product of the two numbers (or formulas).