[tex]\begin{gathered} f(x)=4x+5 \\ g(x)=4-x^2 \\ a)\text{for f(g(0))} \\ f(g(x))=4(4-x^2)+5 \\ f(g(x))=16-4x^2+5 \\ f(g(x))=21-4x^2 \\ f(g(0))=21-4(0)^2 \\ f(g(0))=21-0 \\ f(g(0))=21 \\ b)\text{for g(f(0))} \\ g(f(x))=4-(4x+5)^2 \\ g(f(0))=4-(4(0)+5)^2 \\ g(f(0))=4-(0+5)^2 \\ g(f(0))=4-(5)^2 \\ g(f(0))=4-25 \\ g(f(0))=-21, \end{gathered}[/tex]
