Answer:
[tex](foh)(x)=-x^2 +6x+31[/tex]
Step-by-step explanation:
[tex]\huge f(x)=13-x\ \ \ \ \ \ h(x)=x^2-6x-18 \\ \\(foh)(x)=f[h(x)]=13-(x^2-6x-18)=-x^2 +6x+31[/tex]