Use reduction to establish the undecidability of the each of the decision problems.
Prove that there is no algorithm with input consisting of a Turing machine $\mathbf{M}=$ $\left(\mathrm{Q}, \Sigma, \Gamma, \delta, q_0, \mathrm{~F}\right)$, a tape symbol $x$, and a string $w \in \Sigma^*$ that determines whether the computation of $\mathrm{M}$ with input $w$ prints the symbol $x$.