1.m²（a-2）+m（2-a）2.-4x²yz-12xy²z+4xyz3.45a²-20a4.-x²+4y²5.-4a²b+12ab²-9b³6.4/9m²+3/4mn+n²7.x²-y²-2y-1

Question

1.m²（a-2）+m（2-a）2.-4x²yz-12xy²z+4xyz 3.45a²-20a 4.-x²+4y² 5.-4a²b+12ab²-9b³ 6.4/9m²+3/4mn+n² 7.x²-y²-2y-1

Answer 1

1:=(m^2-m)(a-2)
2:-4x²yz-12xy²z+4xyz
=-4xyz(x+y-1)
3:45a²-20a
=5a(9a-4)
4:-x²+4y²
=4y²-x²
=(2y+x)(2y-x)
5:.-4a²b+12ab²-9b³
=-ab(4a+12b-9b²)
6:4/9m²+3/4mn+n²
=(2m/3+n)²
7：x²-y²-2y-1
=x²-(y²+2y+1)
=x²-(y+1）²
=(x+y+1)(x-y-1)