问题
解答题
先化简，再求值：（
|
答案
原式=[
-x+2 x(x-2)
]+x-1 (x-2)2 x-4 x
=[
-x2-4 x(x-2)2
]+x2-x x(x-2)2 x-4 x
=
+x2-4-x2+x x(x-2)2 x-4 x
=
+x-4 x(x-2)2 x-4 x
=(x-4)(x-2)2 x(x-2)2
=
，x3+20x-16 x(x-2)2
当x=-1时，原式=
=-1-20-16 -1×(-1-2)2
．37 9