先化简再求值[a 1分之2]-搜答案-智慧作业帮

原式=(a-2)/a(a+2)-(a-1)/(a+2)平方=（a平方-2a-a平方+a)/a(a+2)平方=-1/（a+2)平方=-1/5

题目有误吧(x-x)x-1分之4(x-x)+(x-2)再问：(x方-x)(x-2)方再答：

8-2x分之x的平方-16=[(x+4)(x-4)]/[(-2)(x-4)]=-(x+4)/2把x=-2代入上式得：－1

(x-1/x)/((x²-2x+1)/x)=((x²-1)/x)/((x-1)²/x)=(x+1)(x-1)/(x-1)²=(x+1)/(x-1)=6/4=3/

小括号内先通分：分母为x平方-4,分子为3x平方+6x,另一个是x平方-2x化简：{x²-4分之2x²+8x}÷x²-4分之2x结果=x+4

原式=ab(a-2b)分之3a²(a-2b)=b分之3a

=(x+1)(x-1)/x÷(x-2x+1)/x=(x+1)(x-1)/x×[-x/(x-1)==x+1当x=√2时原式=√2+1再问：对不起，是我没说明白x²-1÷(1-x分之2x-1)是

1、原式=2a/(a+2)(a-2)-1/(a-2)=(2a-a-2)/(a+2)(a-2)=1/(a+2)当a=√3-2时,原式=1/√3=√3/3.2、原式=43-12√35.3、原式=15/2√

(x^2-2x+1)/(x^2-1)+1/(x+1)=(x-1)^2/(x+1)(x-1)+1/(x+1)=(x-1)/(x+1)+1/(x+1)=x/(x+1)=1-根2分之一

a^2-1+2-1/a=a^2-1/a+1,a=-3代入,得原式=31/3

分子分母同乘以4.再一化简

解原式=[(a+2)/a²]÷[(a²-4)/a]=(a+2)/a²×a/(a-2)(a+2)=1/a(a-2)=1/(√3)(√3-2)=1/(3-2√3)=(3+2√

（x+1）÷[2+x分之(1+x²)]=（x+1）÷[x分之(2x+1+x²)]=(x+1)÷[x分之(x+1)²]=(x+1)·[(x+1)²分之x]=(x+

原式=x^2/(x-1)+1/(1-x)=(x^2-1)/(x-1)=(x+1)(x-1)/(x-1)=x+1x=-3/2原式=-3/2+1=-1/2如果有疑问请点【评论】或者【追问】再问：-a分之1

原式=-[(x-3)/(x-2)]÷{[(x+2)(x-2)-5]/(x-2)]=-[(x-3)/(x-2)]÷[(x²-9)/(x-2)]=-(x-3)/(x+3)(x-3)=-1/(x+

x+1/2=0,y-1=0x=-1/2,y=1原式=4x²y-(6xy-8xy+4-x²y)+1=4x²y-(-2xy+4-x²y)+1=4x²y+2

（x+3）/（x²-9）+3/（x-3）=（x+3）/（x-3)(x+3)+3/（x-3）=1/（x-3）+3/（x-3）=4/（x-3）代入x=-1/2原式=4/（-1/2-3）=4/（-

（x-2-x+2分之5）÷2x+4分之x-3=（x-2-x+5/2）÷2x＋x/4-3=1/2÷2x＋x/4-3=1/4x＋x/4-3