因为x=1,y=2,故ax-y=a-2=b;3ax+by=3a+2b=6所以a=b+2代入方程式3a+2b=6中得3（b+2)+2b=6,所以b=0,a=2y=2x-3代入方程式3x+2y=1中得3x+2(2x-3)=13x+4x-6=17x=7x=1y=2x-3=-1所以x=1;y=-1
