First, let us define what (fg)(x) is:
[tex](fg)(x)=f(x)\times g(x)[/tex]Given:
[tex]f(x)=2x[/tex][tex]g(x)=\sqrt[]{x+1}[/tex]So the solution to (fg)(x) will be:
[tex]\begin{gathered} =2x\times\sqrt[]{x+1} \\ =2x\text{ }\sqrt[]{x+1} \end{gathered}[/tex]