令2x+3y=m,2x-3y=n m/4+n/3=7 3m+4n=12*7 6m+8n=24*7 m/3+n/2=8 2m+3n=48 6m+9n=48*3 n=48*3-24*7=-24 m=60 2x+3y=60 2x-3y=-24 4x=36 x=9,y=14