Solution
= Solution
Factor the sum before making an <entanglement> claim:
$$
|\Phi\rangle=\frac12\bigl(|+\rangle+|-\rangle\bigr)\otimes\bigl(|0\rangle+|1\rangle\bigr)
=\boxed{|0\rangle\otimes|+\rangle}.
$$
\b[The state is not entangled:] it is a <product state>. A sum written with several tensor-product terms need not be entangled; those terms may combine into a single <tensor product>.