初一因式分解（分组分解题）

6am+4an-3bm-2bn
=3m(2a-b)+2n(2a-b)
=(3m+2n)(2a-b)

2ax+ay+4bx+2by-6cx-3cy
=a(2x+y)+2b(2x+y)-3c(2x+y)
=(a+2b-3c)(2x+y)

给你当家教吧

1.
6am+4an-3bm-2bn
=a(6m+4n)-b(3m+2n)
=2a(3m+2n)-b(3m+2n)
=(2a-b)(3m+2n)

2.
2ax+ay+4bx+2by-6cx-3cy
=a(2x+y)+2b(2x+y)-3c(2x+y)
=(a+2b-3c)(2x+y)

3.
设x^2+y^2=a,得:
a(a-1)-12=0
a^2-a-12=0
(a+3)(a-4)=0
a1=-3,a2=4
即:
x^2+y^2=-3
或
x^2+y^2=4

还元法
X²+y² =Z
Z(z-1)-12=0
Z^2-Z-12=0
△=49
X1=4 X2=-3
x²+y²=4
x²+y²=3