Use ismember() to figure out what rows, then [] to extract all but those rows
A=[ 1 222
2 555
3 999 %----> delete this row
4 3333
6 111
7 5000 %----> delete this row
8 2000]
B=[ 3 7];
[ia, ib] = ismember(A(:, 1), B)
A = A(~ia, :)