初一因式分解 十字相乘 解!!!

来源：百度知道 编辑：UC知道 时间：2024/06/04 20:19:43
1. 6y^2-11y-10

2. 5x^5-15x^3y-20xy^2

6y^2-11y-10
=(2y-5)(3y+2)

5x^5-15x^3y-20xy^2
=5x(x^4-3x^2y-4y^2)
=5x(x^2+y)(x^2-4y)

1. 6y^2-11y-10
=(2y-5)(3y+2)

2. 5x^5-15x^3y-20xy^2
=5x(x^4-3x^2y-4y^2)
=5x(x^2-4y)(x^2+y)

十字相乘法：

1. 6y^2-11y-10

2y -5

3y +2
-------
-15y+4y = -11y

所以 6y^2-11y-10 = (2y-5) (3y-2）.

2. 5x^5-15x^3y-20xy^2
= x(5x^4-15x^2y-20y^2)

5x^2 +5y

x^2 -4y
----------
5x^2y -20x^2y = -15x^2y

所以 5x^5-15x^3y-20xy^2 = x(5x^2+5y)(x^2-4y).

1. 6y^2-11y-10
＝（3Y+2）(2Y-5)
2. 5x^5-15x^3y-20xy^2=5X(X^2-4Y)(X^2+Y)

1.(3y-2)(2y-5)