  We solve the entanglement classification under stochastic local operations
and classical communication (SLOCC) for general n-qubit states. For two
arbitrary pure n-qubit states connected via local operations, we establish an
equation between the two coefficient matrices associated with the states. The
rank of the coefficient matrix is preserved under SLOCC and gives rise to a
simple way of partitioning all the pure states of n qubits into different
families of entanglement classes, as exemplified here. When applied to the
symmetric states, this approach reveals that all the Dicke states |l,n> with
l=1, ..., [n/2] are inequivalent under SLOCC.
