1．3(x-2y)^2-27(3x+y)^2 2．（a＾2＋4b＾2）＾2－16a＾2b＾2 3．3a＾4－2／3a＾2＋1／27

题目

1．3(x-2y)^2-27(3x+y)^2 2．（a＾2＋4b＾2）＾2－16a＾2b＾2 3．3a＾4－2／3a＾2＋1／27
4．2（x＾2－3y＾2）＾2＋24x＾y＾2
5 ．x＾2－10x＋24

答案

1．
3(x-2y)²-27(3x+y)²
=3[(x-2y)²-9(3x+y)²]
=3[(x-2y)+3(3x+y)][(x-2y)-3(3x+y)]
=3(10x+y)(-8x-5y)
=-3(10x+y)(8x+5y)
2.
(a²+4b²)²-16a²b²
=(a²+4b²+4ab)(a²+4b²-4ab)
=(a+2b)²(a-2b)²
=(a²-4b²)²
3.
3aˆ4-2/3aˆ2+1/27
=3(aˆ4-2/9aˆ2+1/81)
=3(a²-1/9)²
4.
2(x²－3y²)²+24x²y²
=2(xˆ4-6x²y²+9yˆ4)+24x²y²
=2(xˆ4-6x²y²+9yˆ4+12x²y²)
=2(xˆ4+6x²y²+9yˆ4)
=2(x²+3y²)²
5.
x²-10x+24
=x²+10x+25-1
=(x-5)²-1
=(x-5+1)(x-5-1)
=(x-4)(x-6)