(gof)(x) means g composed with f or g(f(x))
so
(gof)(20)=g(f(20))
evaluate f(20) then plug that value in for x in g(x)
f(20)=(20-5)^2
f(20)=(15)^2
f(20)=225
now input that for x in g(x)
g(225)=225+[tex] \sqrt{225}-3 [/tex]
g(225)=225+ 15-3
g(225)=237
(gof)(20)=237
