HW 5.1

A={{0,3,1,2},{1,4,0,7},{2,-1,-3,8}};
b={6,5,-8};

p=LinearSolve[A,b]

A.p

B=NullSpace[A]

A.B[[1]]

A.Transpose[B]

RowReduce[A]

Inverse[A]

HW 5.6

Inverse[{{u,v},{w,x}}] //MatrixForm

HW 5.7

CC = {{1,0,3},{0,0,1},{-1,0,-1}};
Inverse[CC]

HW 3.1

linear independent vectors

v={{0,-1,4},{2,1,3},{1,0,-2}};
NullSpace[Transpose[v]]

Inverse[v]