X+1/4=11/12
X=11/12-1/4=8/12=3/2
2/9+X=7/12
x=7/12-2/9=13/36
X-13/36=11/18
X=13/36+11/18=35/36
X-2/3=2/5
X=2/3+2/5=16/15