a={{3,1,4},{100,40,60},{16,22,14}}

MatrixFrom [a]

MatrixFrom[{{3,1,4},{100,40,60},{16,22,14}}]

b={{15},{440},{16}}

{15,440,16}
b1=Matrixform[b]

Matrixform[{15,440,16}]

x=LinearSolve[a,b]

Askisi2

a1={{1,-1,2},{21,1,5},{1,11,6}}

b1=({{2}, {1+k}, {3}})

x1=LinearSolve[a1,b1]

Askisi3

a3=({{1, 2}, {-2, -3}})

b3=Transpose[a3]

b4=Inverse[a3]

Askisi4
a4=({{2, 1, 3}, {1, 1, 2}, {2, 1, 2}})

{{2,1,3},{1,1,2},{2,1,1}}
b4=({{-1}, {2}, {1}})

x4=LinearSolve[a4,b4]

{{-1},{7},{-2}}
a4a=({{2, 1, 3}, {4, 2, -1}, {6, 3, 2}})

b4a=({{0}, {0}, {0}})

x4a=LinearSolve[a4a,b4a]

{{0},{0},{0}}
a4b=({{1, 2, 3}, {1, 3, 2}, {1, 3, l+3}})

b4b=({{-2}, {-1}, {2-k}})

x4b=LinearSolve[a4b,b4b]

Askisi 6

a6=({{1, -4, 7}, {-2, 5, 8}, {3, 6, -9}})

Transpose[a6]//MatrixForm

Inverse[a6]//MatrixForm