解方程x+1\x+2+x+8\x+9=x+2\x+3+x+7\x+8

解方程x+1\x+2+x+8\x+9=x+2\x+3+x+7\x+8
解方程x+1\x+2+x+8\x+9=x+2\x+3+x+7\x+8

解方程x+1\x+2+x+8\x+9=x+2\x+3+x+7\x+8
(x+1)/(x+2)+(x+8)/(x+9)=(x+2)/(x+3)+(x+7)/(x+8)
(x+2-1)/(x+2)+(x+9-1)/(x+9)=(x+3-1)/(x+3)+(x+8-1)/(x+8)
1-1/(x+2)+1-1/(x+9)=1-1/(x+3)+1-1/(x+8)
1/(x+2)+1/(x+9)=1/(x+3)+1/(x+8)
1/(x+2)-1/(x+3)=1/(x+8)-1/(x+9)
1/[(x+2)(x+3)]=1/[(x+8)(x+9)]
(x+2)(x+3)=(x+8)(x+9)
5x+6=17x+72
12x=-66
x=-11/2