Answer :

Sure, let's go through the calculation step-by-step for the given functions [tex]\( f(x) = 6x + 3 \)[/tex] and [tex]\( g(x) = 3 - x^2 \)[/tex].

### Part (a)

We need to find [tex]\( f(g(0)) \)[/tex].

1. First, calculate [tex]\( g(0) \)[/tex]:
[tex]\[ g(0) = 3 - (0)^2 = 3 \][/tex]

2. Next, evaluate [tex]\( f \)[/tex] at [tex]\( g(0) \)[/tex] which is [tex]\( f(3) \)[/tex]:
[tex]\[ f(3) = 6 \cdot 3 + 3 = 18 + 3 = 21 \][/tex]

So, [tex]\( f(g(0)) = 21 \)[/tex].

### Part (b)

We need to find [tex]\( g(f(0)) \)[/tex].

1. First, calculate [tex]\( f(0) \)[/tex]:
[tex]\[ f(0) = 6 \cdot 0 + 3 = 3 \][/tex]

2. Next, evaluate [tex]\( g \)[/tex] at [tex]\( f(0) \)[/tex] which is [tex]\( g(3) \)[/tex]:
[tex]\[ g(3) = 3 - (3)^2 = 3 - 9 = -6 \][/tex]

So, [tex]\( g(f(0)) = -6 \)[/tex].

### Summary:

(a) [tex]\( f(g(0)) = 21 \)[/tex]

(b) [tex]\( g(f(0)) = -6 \)[/tex]