Given that f (x) = 5x+9 and g (x) = 9-x^2

calculate

f (g (0))

g (f (0))

Start from the inside and work your way out

For f (g (0)), g (0) = 9 - (0^2) = 9, f (9) = 5 (9) + 9 = 54

So f (g (0)) = 54

For g (f (0)), f (0) = 5 (0) + 9 = 9, g (9) = 9 - (9^2) = - 72

So g (f (0)) = - 72