[tex]f\left( x \right) =\quad 5x-4\\ g\left( x \right) =\quad { x }^{ 2 }+3x-8\\ g\left( f\left( x \right) \right) [/tex]
for x=3
[tex]f(3)=\quad 5\cdot 3-4\\ f(3)=15-4\\ f(3)=11\\ g(f(3))=g(11)\\ g(11)=\quad { 11 }^{ 2 }+3\cdot 11-8\\ g(11)=\quad 121+33-8\\ g(11)=146[/tex]
I hope this was what you asked for.
