[tex]g\circ f(-9)=g(f(-9))[/tex]
By definition of [tex]f[/tex],
[tex]f(-9)=3\cdot9-8=19[/tex]
and by definition of [tex]g[/tex],
[tex]g\circ f(-9)=g(f(-9))=g(19)=\sqrt{14-19}-10=\sqrt{-5}-10[/tex]
which is undefined if [tex]f,g[/tex] are supposed to be real-valued functions. If they're complex-valued, then [tex]\sqrt{-5}=i\sqrt 5[/tex] and [tex]g\circ f(-9)=-10+i\sqrt 5[/tex].
