①x²-y²-6x+9=（x-3+y）（x-3-y）
②4x²+1/4-2x-9x²=（5x-1/2）（-x-1/2）
x²-y²-6x+9
=x²-6x+9-y²
=(x-3)^2-y^2
=(x-3+y)(x-3-y)
4x²+1/4-2x-9x²
=(2x-1/2)^2-9x^2
=(2x-1/2+3x)(2x-1/2-3x)
=-(5x-1/2)(x+1/2)
x²-y²-6x+9=x²-6x+9-y²=(x-3)²-y²=(x+y-3)(x-y-3)
4x²+1/4-2x-9x² =(2x-1/2)²-9x²=(2x+3x-1/2)(2x-3x-1/2)=(5x-1/2)(-x-1/2)
内容全部来源于网络收集，如有侵权，请联系网站删除：QQ：24596024