Answer :
[tex]\begin{gathered} f(x)=\frac{x-7}{x-6} \\ \end{gathered}[/tex]
we need to evaluate in x=6
[tex]f(6)=\frac{6-7}{6-6}=\frac{-1}{0}[/tex]it is discontinuous in x=6 because we can't divide with 0