问题
解答题
因式分①3(x-y)3+6y(y-x)2;②3x3-18x2+27x.
答案
①3(x-y)3+6y(y-x)2
=3(x-y)3+6y(x-y)2
=3(x-y)2(x-y+2y)
=3(x-y)2(x+y);
②3x3-18x2+27x=3x(x2-6x+9)
=3x(x-3)2.
因式分①3(x-y)3+6y(y-x)2;②3x3-18x2+27x.
①3(x-y)3+6y(y-x)2
=3(x-y)3+6y(x-y)2
=3(x-y)2(x-y+2y)
=3(x-y)2(x+y);
②3x3-18x2+27x=3x(x2-6x+9)
=3x(x-3)2.