7x-21y-x²+6xy-9y²
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/04 06:55:01
![7x-21y-x²+6xy-9y²](/uploads/image/z/15255403-43-3.jpg?t=7x-21y-x%26%23178%3B%2B6xy-9y%26%23178%3B)
7x-21y-x²+6xy-9y²
7x-21y-x²+6xy-9y²
7x-21y-x²+6xy-9y²
7x-21y-x²+6xy-9y²
=7(x-3y)-(x-3y)²
=(x-3y)[7-(x-3y)]
=(x-3y)(7-x+3y)
7x-21y-x²+6xy-9y²=7(x-3y)-(x²-6xy+9y²)=7(x-3y)-(x-3y)²=(7-x+3y)(x-3y)
个人见解,仅供参考。