先化简,再求值:a分之1-根号a的平方加a的平方分之1-2

(a-3分之1-a²-1分之a+1)×(a-3)=(a-3)/(a-3)-(a+1)(a-3)/(a+1)(a-1)=1-(a-3)/(a-1)=(a-1-a+3)/(a-1)=2/(a-1

见附图.再问：额。。那个根号是一直连到a的平方减2的那里的。。。再答：好像已经上传一次了。

a-1分之a的平方-1减a的平方-a分之根号a的平方-2a+1=(a-1)(a+1)/(a-1)-(a-1)²/[a(a-1)]=a+1-(a-1)/a=(a²+a-a+1)/a=

1/(A+B)+1/B+B/A(A+B)=AB/AB(A+B)+A(A+B)/AB(A+B)+BB/AB(A+B)=(AA+2AB+BB)/AB(A+B)=(A+B)/AB=1/A+1/B=4根号5再

根号下a平方+a平方分之1-2减a分之1=√(a-1/a)²-1/a=|a-1/a|-1/a=1/a-a-1/a=-a=-3分之2

2a√(3ab³)-b/6*√(27a³b³)+2ab√(3ab/4)=2ab√(3ab)-a²b/2*√(3ab)+ab√(3ab)=3ab√(3ab)-a&

（a-1/a）=(a²-1)/a=.(a+1)(a-1)/a÷a分之a方+2a+1=÷(a²+2a+1)a=÷(a+1)(a+1)/a=*a/[(a+1)(a+1)]（a-a分之1

原式=[1-1/(a+1)]-[a/(a²+2a+1)]=1-1/(a+1)-a/(a+1)²=(a+1)²/(a+1)²-(a+1)/(a+1)²-

.(a-1分之3a剪a+1分之a)乘以a分之a²剪1=[3a/(a-1)-a/(a+1)]×(a+1)(a-1)/a=3a/(a-1)×(a+1)(a-1)/a-a/(a+1)×(a+1)(

1.(a-√3)(a+√3)-a(a-6)=a^2-3-a^2+6a=6a-3=6(√5+1/2)-3=6√5+3-3=6√52.x^2-5x=14(2x-1)(x-1)-(x+1)^2+1=2x^2

a=1/(2+√3)=2-√3原式=(a+1)(a-1)/(a-1)-√(a-1)²/[a(a-1)]=a+1+(a-1)/[a(a-1)]=a+1+1/a=2-√3+1+1/(2-√3)=

4/(a^2-4)+2/(a+2)-1/(a-2)=4/(a+2)(a-2)+2(a-2)/(a+2)(a-2)-(a+2)/(a+2)(a-2)=[4+2a-4-a-2]/(a+2)(a-2)=(a

a=根号2-1∴a-1

a-1分之根号下a的平方-2a+1+a+1分之1+1=√(a-1)²/(a-1)+1/(a+1)+1=-1+1/(a+1)+1=1/(a+1)=1/(√2)=√2/2;再问：当x时，x分之根

(a-b分之1+b+a分之1)除以a+b分之ab=(b+a+a-b)/[(a+b)(a-b)]×(a+b)/ab=2/[b(a-b)]=2/(ab-b²)=2/(2+根号2-2)=根号2

:(a+根号3)(a-根号3)-a(a-6)=a²-3-a²+6a=6a-3当a=1/2+1/√2时原式=3+3√2-3=3√2

（a+2a+1）/（a-1）-a/(a-1)=(a+1)^2/(a+1)(a-1)-a/(a-1)=(a+1)/(a-1)-a/(a-1)=1/(a-1)由a=根号3+1,所以原式=1/(a-1)=1

原式=(3+a)(3-a)/(a+3)^2x(a+3)/(a-3)a-1/a=-1/a-1/a=-2/a=-2/根号2=-根号2

[1/(a-1)+a/(1-a)]/a=[1/(a-1)-a/(a-1)]/a=[(1-a)/(a-1)]/a=-1/a把a=√2+1代入-1/(√2+1)=-1(√2-1)/(√2+1)(√2-1)

答：a=1/(2+√3)=(2-√3)/[(2+√3)(2-√3)]=(2-√3)/(4-3)=2-√3所以：0