$1.$ Give a formal definition of a two$-$tape Turing machine; then write programs that accept the languages below. Assume that $\backslash$Sigma $=\{$a$,$ b$,$ c$\}$ and that the input is initially all on tape $1.($b$)$ L$=\{$a$^$nb$^$nc$^$m$,$m$>$n$\}$