1、9a² x-b² x-9a²+b²
=9a²(x-1)-b²(x-1)
=(9a²-b²)(x-1)
2、 4x³+4x²y-9xy²-9y³
=4x²(x+y)-9y²(x+Y)
=(4x²-9y²)(x+y)
3、3m-3y-ma+ay
=3(m-y)-a(m-y)
=(3-a)(m-y)
1、9a² x-b² x-9a²+b²
=9a²(x-1)-b²(x-1)
=(9a²-b²)(x-1)
2、 4x³+4x²y-9xy²-9y³
=4x²(x+y)-9y²(x+Y)
=(4x²-9y²)(x+y)
3、3m-3y-ma+ay
=3(m-y)-a(m-y)
=(3-a)(m-y)