Matrix M describes the population:

M:matrix([0,3,3],[0.2,0,0],[0,0.6,x]);

What does it mean, that the population stagnate?

M.M;M.M.M;

We ask, if the matrix hav the eigenvalue 1:

M2:matrix([-1,3,3],[0.2,-1,0],[0,0.6,x-1]);

determinant(M2);

solve(x-0.6*(x-1)-0.64);