即求方程组的交点3X+2Y+Z=392X+3Y+Z=34X+2Y+3Z=26解之得x=71/4y=51/4z=45/4即A交B交C={(71/4,51/4,45/4)}
联立3X+2Y+Z=392X+3Y+Z=34X+2Y+3Z=26 解得x=21/2y=17/4z=11/4
联立三个方程求解就好了