x÷12.5-x÷37.5=1.5 2.5

1+(2x-4)/(x^2-a-2)]/[(x+3)/(x^2-1)]={1+2(x-2)/[(x-2)(x+1)]}(x^2-1)/(x+3)=[1+2/(x+1)](x+1)(x-1)/(x+3)

(x+1)(x²-x+1)+6x³÷(-2x²)+(-x^6)÷x^4,=x³+1-3x-x^2,=x^3-x^2-3x+1=-8-4+6+1=-5

原式=(1+x²)/(1+x)(1-x)÷(2x-x+x²)/(1-x)=(1+x²)/(1+x)(1-x)×(1-x)/x(x+1)=(1+x²)/x(1+x

(x+1-1/1-x)÷(x-x²/x-1)=[(x+1)+1/(x-1)]×[-(x-1)/x(x-1)]=(x²-1+1)/(x-1)×(-1/x)=-x/(x-1)(x-4/

原式=（x+1)²(x-1)/x(x-1)×2x/(x+1)²+x=2+x当x=1+√3时原式=3+√3再问：步骤能不能再详细点，有点蒙。再答：

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

x+1/x除以（x-1+x²/2x）=(x+1)/x÷(2x^2-1-x^2)/2x=2(x+1)/(x^2-1)=2(x+1)/(x+1)(x-1)=2/(x-1)已知x=√2+1x-1=

先化简,再求值：（1）（x+1/x²-x-x/x²-2x+1）÷1/x,x=根号2+1急!=((x+1)/x(x-1)-x/(x-1)²)×x=(x+1)/(x-1)-x

x=1/x所以x=±1原式=(x+2)÷[(x+3)(x-3)/(x+3)]=(x+2)/(x-3)所以x=-1,原式=(-1+2)/(-1-3)=-1/4x=1,原式=(1+2)/(1-3)=-3/

（x+2/x²-2x-x-1/x²-4x+4）÷x-4/x={(x+2)(x-2)/[x(x-2)²]-x(x-1)/[x(x-2)²]}·x/(x-4)={(

注意：本题x=2时题目没意义,应该舍去（这是很多学生错误所在）这里x只能取根号2-1  

(x^2-1)=（x+1）*（x-1）(x^2+x)=x（x+1）通分x-(2x-1)/x=（(x^2-2x+1）/x=（x-1)^2/x带回写成分式后发现约掉一个x,一个（x+1）,一个（x-1）化

原式=x^2+4x+4x^2-1-4x^2-4x=x^2-1代入x=-2原式=3

(x-3)/(x^2-1)÷(x^2-2x-3)/(x^2+2x+1)+1/(x-1)=(x-3)/(x^2-1)*(x^2+2x+1)/(x^2-2x-3)+1/(x-1)=(x-3)/(x-1)(

2x-6/4-4x+x^2÷x-3/x-2=-2x-7/2+x-3/x=-x-3/x-7/2=1+3-7/21/2

 再答：采纳哟

x(1−21−x)÷(x+1)−x(x2−1)x2−2x+1=x[1−x−21−x•1x+1−(x−1)(x+1)(x−1)2]=x(1x−1−x+1x−1)=−x2x−1，∵x2+x-1=0，∴-x

第一题：x-x/5=2.45x-x=124x=12x=3第二题：12/5%x=8240x=8x=1/30第三题：4x+x=12.55x=12.5x=2.5

=[3/(x+1)-(x-1)]÷(x²-2x)/(x+1)=[3/(x+1)-(x-1)(x+1)/(x+1)]÷x(x-2)/(x+1)=[3-(x+1)(x-1)]/(x+1)÷x(x

x(2-1/x)+x/(x^2-2x)÷(3-x)/(x^2-4)=x((2x-1)/x)+x/(x^2-2x)x(x^2-4)/(3-x)=(2x-1)+(x+2)/(3-x)=(7x-3-2x^2