We are given the functions f(x) = x^2 + 4 and g(x) = sqrt(x- 4)

fog(x) = f (g(x)) = f (sqrt (x- 4))

=> (sqrt (x – 4)) ^2 + 4

=> (x – 4) + 4

=> x

**Therefore fog (3) = 3.**

We are given the functions f(x) = x^2 + 4 and g(x) = sqrt(x- 4)

fog(x) = f (g(x)) = f (sqrt (x- 4))

=> (sqrt (x – 4)) ^2 + 4

=> (x – 4) + 4

=> x

**Therefore fog (3) = 3.**