method 1
a=[1 2 3;4 5 6;7 8 9];
k=0;
for i=1:3;
for j=1:3;
a(i,j)
if a(i,j)>5
k=k+1;
b(k)=a(i,j);
end
end
end
method 2
b=a(a>5);