You might want the two output version of FIND. The one output version does not return the row number, but the linear index.
x = magic(6); % Sample data
[I,J] = find(x>10); % I is rows, J is columns.
Now if your goal is only to subtract 2 from the values of x which are greater than 10, and whos row and column position are greater than two (as I read your somewhat confusing post), do this:
idx = I>2 & J>2;
idx = sub2ind(size(x),I(idx),J(idx));
x(idx) = x(idx)-2
Note, if you want to display the positions, you could just use:
x>10 % Shows in command window
spy(x>10) % Shows a graph.
