Question 1140462
1 0 0 0 | −3
0 1 0 0 | 4
0 0 1 0 | −4
0 0 0 1 | 0 

{{{x[1]=-3 }}} 
{{{x[2]=4}}} 
{{{x[3]=-4}}} 
{{{x[4]=0}}}