x²-1-ax+a² 2.x²-y²-4x+4 3.16+8xy-16x
2个回答

解1:

x²-1-ax+a²=x²-ax+a²-1

=x(1-a)+(a+1)(a-1)

=x(1-a)-(a+1)(1-a)

=(1-a)(x-a-1)

解2:

x²-y²-4x+4=x²-4x+4-y²

=(x-2)²-y²

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

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

解3:

16+8xy-16x²-y²=16-(16x²-8xy+y²)

=16-[(4x)²-8xy+y²]

=16-(4x-y)²

=[4-(4x-y)][4+(4x-y)]

=(4-4x+y)(4+4x-y)

解4:

已知:x²-x-1=0,

求:-3x²+2x²+2008

此题似乎有问题,楼主确认没有抄写错误吗?