Let O be a bounded domain in Rn with n = 3. In this paper we are concerned with the problem of finding u I H01 (O) satisfying the nonlinear elliptic problems ?u + |u|(n+2/n-2) + f(x) = 0 in O and u(x) = 0 on ?O, and ?u + u + |u|(n+2/n-2) + f(x) = 0 in O and u(x) = 0 on ?O, when of f I L8(O).