这个题目刚答过系数矩阵A=12-22-112-13-224-711r2-r1,r3-2r112-22-10011-100-3-33r1+2r2,r3+3r21204-30011-100000a1=(-2,1,0,0,0)^T,a2=(4,0,1,-1,0)^T,a3=(3,0,1,0,1)^T是一个基础解系,方程组的通解为c1a1+c2a2+c3a3,c1,c2,c3为任意常数