4、4a²-(a²+1)² 5、1-a²+ab-1/4b² 6、 x&
1个回答

4、4a²-(a²+1)²

=(2a-a²-1)(2a+a²+1)

=-(a²-2a+1)(a+1)^2

=-(a-1)^2(a+1)^2

5、1-a²+ab-1/4b²

=1-(a²-ab+1/4b² )

=1-(a-1/2b)²

=(1-a+1/2b)(1+a-1/2b)

6、 x³-x²y-xy²+y³

=x(x²-y²)-y(x²-y²)

=(x²-y²)(x-y)

=(x+y)(x-y)^2

7、(x²+4x)²-8(x²+4x)+16

=(x²+4x)(x²+4x-4)-4(x²+4x-4)

=(x²+4x-4)(x²+4x-4)

8、(x+2)(x-2)-4y(x-y)

=x²-4-4xy+4y²

=x²-4xy+4y²-4

=(x-2y)²-4

=(x-2y+2)(x-2y-2)