x = 3;
y = 5;
z = x + y;

n=3; 
m=3;
x = zeros(n, m);

x =
     0     0     0

     0     0     0

     0     0     0

n=3;
m=3;
x = ones(n,m);

x =
     1     1     1

     1     1     1

     1     1     1

A = [1 2 3 ; 4 5 6 ; 7 8 9] ;

A =
     1     2     3

     4     5     6

     7     8     9

A = [1 3 5 ; 7 9 11 ; 13 15 17] ;
В = [2 4 6 ; 8 10 12 ; 14 16 18] ;
C = A+B;
D = A-B;

C =
     3     7    11  

    15    19    23

    27    31    35
D =
    -1    -2    -3

    -4    -5    -6

    -7    -8    -9

F = A*B ;

F =
    96   114   132

   240   294   348

   384   474   564

E =  A.*B ;

E =
     2    12    30

    56    90   132

   182   240   306

X = [1 0 2; -1 5 0; 0 3 -9];
Y = inv(X);

Y =
    0.8824   -0.1176    0.1961

    0.1765    0.1765    0.0392

    0.0588    0.0588   -0.0980

 size(A);
     3     3

u=A(1,:);

u =
     1     3     5

v=A(:,1);

v =
     1

     7

    13

w=A(2,3);

A(3,2)=10;

A =
     1     3     5

     7     9     11

    13    10    17

z = diag (A);

z = 1 9 17