一道利用初等行变换计算矩阵的逆的题

{1,1,2,1,0,0},
{1,2,1,0,1,0},
{2,6,2,0,0,1 }
{1,1,2,1,0,0},
{0,1,-1,-1,1,0},
{0,3,-1,-1,-1,1}
{1,0,3,2,-1,0},
{0,1,-1,-1,1,0},
{0,0,2,2,-4,1}
{一行 - 三行*3/2},
{二行 + 三行/2},
{三行/2}
{1,0,0,-1,5,-3/2},
{0,1,0,0,-1,1/2},
{0,0,1,1,-2,1/2}