因式分解 难难难难

来源：百度知道 编辑：UC知道 时间：2024/05/22 14:56:23
1.2x^2-3x-6xy+9y
2.ab-bc-ac-b^2
3.4x^3-12x^2-x+3
4.7x^2-3y+xy-21x
5.5m^2(a+b)-a-b
抱歉
第2题
ab-bc+ac-b^2

1.2x^2-3x-6xy+9y
=x(2x-3)-3y(2x-3)
=(2x-3)(x-3y)

2.ab-bc+ac-b^2
=a(b+c)-b(b+c)
=(b+c)(a-b)

3.4x^3-12x^2-x+3
=4x^2(x-3)-(x-3)
=(x-3)(4x^2-1)
=(x-3)(2x+1)(2x-1)

4.7x^2-3y+xy-21x
=7x(x-3)+y(x-3)
=(x-3)(7x+y)

5.5m^2(a+b)-a-b
=5m^2(a+b)-(a+b)
=(a+b)(5m^2-1)

1.=2x^2-6xy-3x+9y
=2x(x-3y)-3(x-3y)
=(2x-3)(x-3y)
2.有问题？？
3.=4x^2(x-3)-(x-3)
=(4x^2-1)(x-3)
=(2x+1)(2x-1)(x-3)
4.=7x(x-3)+y(x-3)
=(7x+y)(x-3)
5.=5m^2(a+b)-(a+b)
=(5m^2-1)(a+b)