3/(2x-4)+x/(2-x)=1/2
3/[2(x-2)]+x/(2-x)-1/2=0
(3+2x-2x+4)/[2(x-2)]=0
7/[2(x-2)]=0 无解
(x+3)/(x+2)+1=1/(2+x)
(x+3)/(x+2)+1-1/(2+x) =0
(x+3+x+2-1)/(x+2) =0
2(x+2)/(x+2) =0
2=0,无解
(2x+5)/(3x-6)-1/2=(4-5x)/(4-2x)
(2x+5)/(3x-6)-1/2-(4-5x)/(4-2x)=0
(2x+5)/[3(x-2)]-1/2-(4-5x)/[-2(x-2)]=0
(2x+5)/[3(x-2)]-1/2+(4-5x)/[2(x-2)]=0
[2(2x+5)-3(x-2)+3(4-5x)] / [6(x-2)]=0
[4x+10-3x+6+12-15x] / [6(x-2)]=0
-14[x-2] / [6(x-2)]=0
-14 / 6=0,无解