先化简再求值（3x/x-1-x/x+1)*x^2-1/2x，其中x=-3
先化简再求值（3x/x-1-x/x+1)*x^2-1/2x，其中x=-3
（3x/x-1-x/x+1)*x^2-1/2x，其中x=-3
=(3x^2+3x-x^2+1)/(x-1)(x+1)*(x+1)(x-1)/2x
=(2x^2+x+1)/2x
=x+1/2+1/2x
=-3+1/2-1/6
=-8/3
先化简,再求值:(3x/x-1-x/x+1)×x^2-1/x，其中,x=(根号2)-2
(3x/x-1-x/x+1)×x^2-1/x
=[3x(x+1)-x(x-1)]/[(x-1)(x+1)]*(x^2-1)/x
=(2x^2+4x)/x
=2x+4
因为x=(根号2)-2,
所以
原式=2*(√2-2)+4
=2√2.
先化简,再求值:(3x/x-1-x/x+1)×(x-1/x)，其中x=2.
(3x/x-1-x/x+1)×(x-1/x)
=[3x/(x-1)-x/(x+1)]×[(x-1)/x]
=[(3x(x+1)-x(x-1))/(x+1)(x-1)]×[(x-1)/x]
=(3x^2+3x-x^2+x)/x(x+1)
=(2x^2+4x)/x(x+1)
=2x(x+2)/x(x+1)
=2(x+2)/(x+1)
=2(2+2)/(2+1)
=8/3
先化简,再求值(1)(3x-3)/(x^2-1)÷3x/(x+1)-1/(x-1),其中x=2
(3x-3)/(x^2-1)÷3x/(x+1)-1/(x-1)
=3(x-1)/(x+1)(x-1)*(x+1)/3x-1/(x-1)
=1/x-1/(x-1)
=(x-1-x)/x(x-1)=1/x(1-x)=1/[2*(-1)=-1/2
(x^2+2x+1)/（x+2）÷(x^2-1)/(x-1)-1/(x+2)
=(x+1)^2/(x+2)*(x-1)/(x+1)(x-1)-1/(x+2)
=(x+1)/(x+2)-1/(x+2)
=x/(x+2)=1/2/(1/2+2)=1/2*2/5=1/5
先化简，再求值：（3x/x-1 － x/x+1）· x²-1/x ，其中 x=根号2 －2
最终结果：2倍根号2
（3x/x-1 － x/x+1）· x²-1/x=[3x（x+1）-x(x-1)/x²-1]x²-1/x=（3x²+3x-x²+x）/x=2x+4
再带入数值就行了
先化简 再求值,(3X/X-1 --X/X+1)X X平方-1/X 其中X=根号2-2
要不是我超强的理解能力(旁边有人吐了)都看不懂你的题,写的有点不清楚
以后问问题要当心哦!
进入正题:
解:原式={[3x(x+1)-x(x-1)]/(x-1)(x+1)}*(x-1)(x+1)/x
=[3x(x+1)-x(x-1)]/x=(3x平方+x-x平方+x)/x=2x+4
当x=根号2-2时
原式=2x+4=2(根号2-2)+4=2倍根号2-4+4=2倍根号2
答:...
祝你中考成功!!!
先化简,再求值:[(x-3)/(x^2-2x-3)-x/(x^2-1)]÷1/(x+1),其中x=-1/2
:[(x-3)/(x^2-2x-3)-x/(x^2-1)]÷1/(x+1),
=[(x-3)/(x-3)(x+1)-x/(x+1)(x-1)]×(x+1_
=1-x/(x-1)
=(x-1-x)/(x-1)
=-1/(x-1)
当x=-1/2时
原式=-1/(-1/2-1)=2/3
先化简再求值 x^2-2x[1/2x^2-3(1/3x-1)] 其中x=-1/3
解：由x=-1/3得
x^2-2×[1/2x^2-3(1/3x-1)]
=x^2-2×(1/2x^2-x+3)
=x^2-(x^2-2x+6)
=x^2-x^2+2x-6
=2x-6
=2×（-1/3）-6
=-2/3-6
=-6又2/3
先化解再求值：（3x/x+1-x/x-1)*x^2-1/x-2,其中x=根号3/2
[3x/(x+1) -x/(x-1)]*(x²-1)/(x-2)
=[3x/(x+1) *(x²-1) -x/(x-1) *(x^2-1)]÷(x-2)
=[3x(x-1)-x(x+1)]÷(x-2)
=(3x²-3x-x²-x)÷(x-2)
=(2x²-4x)÷(x-2)
=2x
=2*根号3/2
=根号3
