增广矩阵= 1 2 -1 2 1 2 4 1 1 5-1 -2 -2 1 -4r2-2r1,r3+r11 2 -1 2 10 0 3 -3 30 0 -3 3 -3r3+r2,r2*(1/2),r1+r21 2 0 1 20 0 1 -1 10 0 0 0 0方程组的通解为 (2,1,0,0)^T+c1(2,-1,0,0)^T+c2(1,0,-1,-1)^T