3x-4y=3x+2y=1x=1-2y3(1-2y)-4y=33-6y-4y=310y=0解得y=0 x=1
X=1-2y3(1-2y)-4y=33-6y-4y=3y=0y=0代入3X-4y=3,则3X-4×0=3X=1X=1、y=0