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 x2(x-2)
=
×(x+2)(x-2)-x(x-1) x(x-2)2 x2(x-2) x-4
=
×x2-4-x2+x x(x-2)2 x2(x-2) x-4
=
×x-4 x(x-2)2 x2(x-2) x-4
=
,x x-2
当x=-2时,原式=
=-2 -2-1
.2 3
先化简,再求值:(
|
原式=(
-x+2 x(x-2)
)÷x-1 (x-2)2 x-4 x2(x-2)
=
×(x+2)(x-2)-x(x-1) x(x-2)2 x2(x-2) x-4
=
×x2-4-x2+x x(x-2)2 x2(x-2) x-4
=
×x-4 x(x-2)2 x2(x-2) x-4
=
,x x-2
当x=-2时,原式=
=-2 -2-1
.2 3