解{x-3y 4 y 5 3=2x-7

(x+3)/(x+2)+(x+9)/(x+8)=(x+5)/(x+4)+(x+7)/(x+6)1+(x+5)/(x+2)(x+8)=1+(x+5)/(x+4)(x+6)x=-5再问：第二步那个1是怎么

2（x-2)(x+3)-(2x-5)(x-1)=3x+72（x²+x-6）-（2x²-7x+5）=3x+72x²+2x-12-2x²+7x-5=3x+79x-1

((X-2)(X-4)-(X-3)^2)/(X-3)(X-4)=((X-5)(X-7)-(X-6)^2)/(X-6)(X-7),-1/(X^2-7X+12)=-1/(X^2-13X+42),6X=30

x(x^2-2)+2x^2(x+3)-3x(5x-7)=x(3x^2-9x+17)+2=>x^3-2x+2x^3+6x^2-15x^2+21x=3x^3-9x^2+17x+2=>2x=2x=1

x(1+2+...+9)=x(9-8-7-...-1)x=0记得采纳啊

2x+3x+4x+5x+x+6x+7x=10028x=100x=100/28x=25/7

我给个思路吧（X+2-1/X+2)-(X+3-1/X+3)=（X+6-1/X+6)-(X+7-1/X+7)1-1/(X+2)-1+1/(X+3)=1-1/(X+6)-1+1/(X+7)剩下的就自己解决

2x²-x-3-x²-x+2=x²+7x²-2x-1=x²+72x=-8x=-4

 再问：2x是怎么得来的

方程两边同时乘以x²-1:(3x²+9x+7)(x-1)-(2x²+4x-3)(x+1)-(x³+x+1)=03x^3+9x^2+7x-3x^2-9x-7-(2

通分得[（x-8）(x-4)-(x-9)(x-3)]/(x-3)(x-4)=[(x+7)(x+3)-(x+2)(x+8)]/(x+8)(x+3)解得5/(x-3)(x-4)=5/(x+8)(x+3),

x/(x-2)=2x/(x-3)+(1-x)/(x-5x+6)x/(x-2)=2x/(x-3)+(1-x)/(x-2)(x-3)x(x-3)/(x-2)(x-3)=2x(x-2)/(x-2)(x-3)

(x+8)/(x-3)-(x-9)/(x-4)=(x+7)/(x+8)-(x+2)/(x+3)[（x-8）(x-4)-(x-9)(x-3)]/(x-3)(x-4)=[(x+7)(x+3)-(x+2)(

7/(x^2+x)+3/(x^2-x)=6/(x^2-1)7/x(x+1)+3/x(x-1)=6/(x-1)(x+1)分子分母同乘以x(x-1)(x+1),得7（x-1）+3（x+1)=6x10x-4

通分化简得到(x+1)(x+2)=(x+5)(x+6)3x+2=11x+308x=-28x=-7/2

（x+1)/(x+2)+(x+6)/(x+7)=(x+2)/(x+3)+(x+5)/(x+6)(x+2-1)/(x+2)+(x+7-1)/(x+7)=(x+3-1)/(x+3)+(x+6-1)/(x+

首先由题意得x+1≠0,x+7≠0,x+5≠0,x+3≠0,即x≠-1,x≠-7,x≠-5,x≠-3,则先简化方程(x+1+1)/(x+1)+(x+7+1)/(x+7)=(x+5+1)/(x+5)+(

2(x-3)(x+5)=x^2+(x+2)(x-2)+(x+7)2(x^2+2x-15)=x^2+x^2-4+x+72x^2+4x-30=2x^2+x+33x=33x=11

(1/x-7)+(1/x-1)=(1/x-6)+(1/x-2)1/(X-7)-1/(X-6)=1/(X-2)-1/(X-1)(X-6-X+7)/[(X-7)(X-6)]=(X-1-X+2)/[(X-1

这个展开就行了哇.2*（x^2+x-6）-(2*x^2-7X+5)-3x-7=0化简得：6X=24x=4应该是对的.嘿嘿.