Apply the Laplacian Filter in Matlab

I have a question. I tried many time with different codes but i did not find answer. I am not sure in every time about my answer. I wonder how to find answer using with matlab.

I tried codes:

A=[14 12 10 12 11 10 13 7 9 16;

16 14 13 13 12 6 9 10 13 11;

16 14 12 13 11 8 9 11 11 3;

13 13 12 12 15 11 12 12 4 3,

16 9 4 12 14 8 9 21 11 5;

16 15 15 12 8 8 5 5 6 12;

12 11 13 11 13 4 4 3 2 5;

7 7 13 13 14 4 4 3 4 5;

8 11 5 12 12 4 5 4 4 5;

14 14 12 6 12 5 2 3 5 3]

%my first try

kernel = -1 * ones(3);

kernel(2,2) = 8; % Now kernel = [-1,-1,-1; -1,8,-1; -1,-1,-1]

output = conv2(A,kernel,'same');

%my second try

b=[0 1 0; 1 -4 1; 0 1 0]

c=conv2(A,b,'valid')

%my third try

b=[-1,-1,-1; -1,8,-1; -1,-1,-1]

c=conv2(A,b,'valid')

%my 4th try

A=uint8(A);

H = fspecial('laplacian',0,2)

T=imfilter(A,H);

I would be glad if you help.