I believe the equation is
[tex]4 \sqrt[4]{2x} + 6 \sqrt[4]{2x} [/tex]
In this case, you would simplify it by adding them together.
[tex]4 \sqrt[4]{2x} + 6 \sqrt[4]{2x} [/tex] = [tex]10 \sqrt[4]{2x} [/tex]
And can even be changed to an exponential equation:
[tex]10(2x)^{ \frac{1}{4} } [/tex]