8x-4(20-x)=100解方程

(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

将x-7/x-9分解成1+2/(x-9)其他分式同理则原方程等价于1/x-9+1/x-5=1/x-6+1/x-81/x-6-1/x-5=1/x-9-1/x-81/(x-5)(x-6)=1/(x-8)(

[1-1/(x-4)]+[1-1/(x-8)]=[1-1/(x-7)]+[1-1/(x-5)]1/(x-4)+1/(x-8)=1/(x-7)+1/(x-5)(x-4+x-8)/(x-4)(x-8)=(

x(2x-4)+3x(x-1)=5x(x-3)+82x²-4x+3x²-3x=5x²-15x+88x=8x=1

(x/x(x+2))+(x/(x+2)(x+4))+.+x/(x+8)(x+10)=(x/2)*(2/x(x+2))+(2/(x+2)(x+4))+.+2/(x+8)(x+10)=(x/2)*[1/x

（X+X)+(X-X)+(X*X)+(X/X)=1002X+0+X*X+1=1002X+X*X=99X(X+2)=99X=9再问：请问X(X+2)=99解为什么就等于9了呢没看懂再答：换成算术法你就明

2x+4x+6x...+100x=1-(x+3x+5x+...+99x)x(2+4+6+...+100)=1-x(1+3+5+...99)x(2+4+6+...+100)+x(1+3+5+...+99

（2x+5)(4x*x-10x+25)=8x(x*x+1)8x^3-20x^2+50x+20x^2-50x+125=8x^3+8x,8x=125,x=125/8或利用立方和公式8x^3+125=8x^

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),

设x1=4-√3,x2=4+√3,是方程X^2-8X+13=0的两根所以X1^2-8X1+15=2X^4-6X^3-2X^2+18X+23=(X+1)^2*(X^2-8X+13)+10=10所以原式=

(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)(

这道题不用那么复杂.先移项.(x-4)/(x-5)-(x-5)/(x-6)=(x-7)/(x-8)-(x-8)/( x-9)再通分.（x-4)(x-6)/(x-5)(x-6)-(x-5)(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)+(

2x+4x+6x+8x+...+2010x+2012x=1013042x+2x+3x+4x+...+1005x+1006x=5065211006*1007x/2=506521x=1013042/100

左右两边同乘以(X-5)(X-6)(X-8)(X-9)得到(X-4)(X-6)(X-8)(X-9)-(X-5)(X-5)(X-8)(X-9)=(X-5)(X-6)(X-7)(X-9)-(X-5)(X-

(x-4)/(x-5)-(x-5)/(x-6)=(x-7)/(x-8)-(x-8)/(x-9)1+1/(x-5)-1-1/(x-6)=1+1/(x-8)-1-1/(x-9)1/(x-5)-1/(x-6

x-4/x-5-x-5/x-6=x-7/x-8-x-8/x-91+1/x-5-1-1/x-6=1+1/x-8-1-1/x-91/x-5-1/x-6=1/x-8-1/x-9-1/(x-5)(x-6)=-

2x+4x+6x+8x~+2010x+2012x=1013042（2+2012)×1006÷2×x=1013042x=1再问：可以分解仔细点吗？再答：（2+2012)×1006÷2×x=1013042

x-x/7-(x/12+x/8)-(x/4+x/20+x/5)=500x-x/7-(5/24)x-x/2=500(1/2-5/24)x-x/7=500(7/24)x-x/7=50049x-24x=50

(x-4)/(x-5)+(x-8)/(x-9)=(x-7)/(x-8)+(x-5)/(x-6)1+1/(x-5)+1+1/(x-9)=1+1/(x-8)+1+1/(x-6)1/(x-5)+1/(x-9