Answer :
Solving the given equation,
[tex]\begin{gathered} \sqrt[]{x+1}+3=0 \\ \sqrt[]{x+1}=-3 \\ (\sqrt[]{x+1})^2=(-3)^2 \\ x+1=9 \\ x=8 \end{gathered}[/tex]Substituting the value of x in the original equation,
[tex]\begin{gathered} g(x)=\sqrt[]{8+1}+3 \\ =\sqrt[]{9}+3 \\ =6\ne0 \end{gathered}[/tex]Thus, x=8 is an extraneours solution.