先化简,再求值:(x-x 1分之3x)

原式=(x+4)(x-4)分之(x-4)²=(x+4)分之(x-4)=(5+4)分之(5-4)=9分之1

解x/(x+2)-(x²+2x+1)/(x+2)÷(x²-1)/(x-1)=x/(x+2)-(x+1)²/(x+2)÷(x-1)(x+1)/(x-1)=x/(x+2)-(

[x/(x-2)-x/(x+2)]÷[4x/(x-2)]=[x(x+2)-x(x-2)]/[(x-2)(x+2)]×[(x-2)/4x]=4x/[(x-2)(x+2)]×[(x-2)/4x]=1/(x

原式=[3x(x+1)-x(x-1)/x^2-1]×(x^2-1/2x)上面化到最后=[2x(x+2)/x^2-1]×x^2-1/2x=x+2当x=3时,原式=-3+2=-1(在键盘上打这个好辛苦啊~

x+2分之x-x+2分之x平方+2x+1除以x-1分之x平方-1=[x/(x+2)-(x²+2x+1)/(x+2)]÷(x²-1)/(x-1)=[(x-x²-2x-1)/

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

x/(x-3)-3x/(x^2-3x)-3/x通分得=x^2/(x^2-3x)-3x/(x^2-3x)-3*(x-3)/(x^2-3x)=(x^2-3x-3x+9)/(x^2-3x)=(x-3)(x-

(x-1分之x平方-1-x分之2x)除以x-1分之x,其中x=根号3+1=[x²/(x-1)+2x/(x-1)]÷x/(x-1)=x(x+2)/(x-1)*(x-1)/x=x+2其中x=根号

你写的看不懂分子分母的代数式用括号括起来否则分不出来先通分【（（x-2）(x+2)-x(x-1)）/x(x+2)(x+2)】(x+2)/(x-4)=(x-4)/x(x+2)(x-4)=1/x(x+2)

（1+1/(x-1))÷x/(x²-1)=x/(x-1)÷x/(x+1)(x-1)=x/(x-1)×(x+1)(x-1)/x=x+1代入可得结果等于-1

(X+3)的平方-X的平方=X的平方+6X+9-X的平方=6X+9=6*5/4+9=7.5+9=16.5再问：貌似不是再答：怎么叫貌似不是？(X+3)的平方就是X的平方+6X+9.减去X的平方就是6X

1、(x-3分之2x-x+3分之x)乘x分之x平方-9=［2X(X+3)-X(X-3)］/［(X-3)(X+3)］*(X+3)(X-3)/X=［2X^2+6X-X^2+3X］/X=X+9当X=1时,原

（x-1分之3x-x+1分之x）*x分之x的平方-1=[3x(x+1)-x(x-1)]/x=3(x+1)-(x-1)=3x+3-x+1=2x+4=2√2-4+4=2√2再问：确定么再答：确定啊，楼下也

原式=(x-1)(x+1)/(x+2)*(x+2)/x-1=x+1然后代入数值即可很高兴为您解答,【学习宝典】团队为您答题.请点击下面的【选为满意回答】按钮,

[3x/(x-1)-x/(x+1)]×(x²-1)/x=x[3(x+1)-(x-1)]/(x²-1)×(x²-1)/x=2x+4当x=√2-2时,原式=2x+4=2√2

原式＝[2x(x+2)-x(x-2)]/(x²-4)＋x/(x²-4)＝(x²+7x)/(x²-4)＝[x(x+7)]/[(x+2)(x-2)]代入x＝5原式＝

=（x+1）/（（2*x+1+x^2）/x）=（x+1）/（（x+1）^2/x）=（x+1）*x/（x+1）^2=x/（x+1）代入x=-3/2得到：原式=3

原式=(x+2)(x+3)x+3•x−3(x+2)(x−2)−1=x−3x−2−x−2x−2=−1x−2；当x=3时，原式=−13−2=2+3．

（x²-1分之x-3）÷（x²+2x+1分之x²-2x-3)-(x+1分之1）=(x-3)/(x+1)(x-1)×(x+1)²/(x-3)(x+1)-1/(x+