$(1$ point$)$ Alice and Bob are using the ElGamal cipher with the parameters p $=193$ and a $==5.$

Alice makes the mistake of using the same ephemeral key for two plaintexts, x$\_1$ and x$\_2.$ The eavesdropper Eve suspects that x$\_1=146.$ She sees the two ciphertexts y$\_1=141$ and y$\_2=167$ in transit; these are the encryptions of x$\_1$ and x$\_2,$ respectively.

a$)$ What is the masking key k$\_$M$?$

b$)$ What is the plaintext x$\_2?$