[latex] left { {{x-3=1} atop {y+4=12}} ight. =>x=4,y=8[/latex] [latex] left { {{x-3=3} atop {y+4=4}} ight. =>x=6,y=0[/latex] [latex] left { {{x-3=2} atop {y+4=6}} ight. =>x=5,y=2[/latex]