Question

因式分解

九年级的题，和高中接轨.... 题目没有出错

Answer 1

令3x²+4xy-y²=0
带入求根公式
x=（-4y±2√7y）/6=（-2y±√7y)/3
3x²+4xy-y²=3(x-x1）（x-x2）=3【（x-（-2y+√7y)/3】【x-
（-2y-√7y)/3】

Answer 2

=2x2+x2-2xy+y2-2xy-2y2
=2(x2-y2)+(x-y)2
=(x-y)[2(x+y)+(x-y)]
=(x-y)(3x+y)

凡字母x、y后面的数2为平方

Answer 3

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

Answer 4

原式=3(x²+4xy/3)-y²
=3(x²+4xy/3+4y²/9-4y²/9)-y²
=3(x²+4xy/3+4y²/9)-4y²/3-y²
=3[(x+2y/3)²-7y²/9]
=3(x+2y/3+√7y/3)(x+2y/3-√7y/3)