[tex]f(g(h(x)))=f(g(\sqrt x))=f(\sqrt x-1)=\boxed{(\sqrt x-1)^4+4}[/tex]
This is because
[tex]h(x)=\sqrt x[/tex]
[tex]g(x)=x-1[/tex]
[tex]\implies g(h(x))=\sqrt x-1[/tex]
(that is, replace any instance of x in the definition of g with √x )
and
[tex]f(x)=x^4+4[/tex]
[tex]\implies f(\sqrt x-1)=(\sqrt x-1)^4+4[/tex]
(replace any x in f with √x - 1)
Also acceptable:
[tex](\sqrt x-1)^4+4=((\sqrt x)^4-4(\sqrt x)^3+6(\sqrt x)^2-4\sqrt x+1)+4[/tex]
[tex]=\boxed{x^2-4x\sqrt x+6x-4\sqrt x+5}[/tex]
(assuming x is not negative)
