m(a-3)+2(3-a)=(a-3)(m-2)
(x+2)(x+3)+x.x-4看不懂
-3x²+6xy-3y²=-3(x²-2xy+y²)=-3(x-y)²
2010+2010²-2011²=2010(1+2010)-2011²=2011(2010-2011)=-2011
m(a-3)+2(3-a)=(a-3)(m-2)
(x+2)(x+3)+x.x-4看不懂
-3x²+6xy-3y²=-3(x²-2xy+y²)=-3(x-y)²
2010+2010²-2011²=2010(1+2010)-2011²=2011(2010-2011)=-2011