$7\sqrt{ 3 }-4\sqrt{ 6 }+4\sqrt{ 3 }-\sqrt{ 54 }$
Simplify the radical expression$7\sqrt{ 3 }-4\sqrt{ 6 }+4\sqrt{ 3 }-3\sqrt{ 6 }$
Collect like terms$11\sqrt{ 3 }-4\sqrt{ 6 }-3\sqrt{ 6 }$
Collect like terms$\begin{align*}&11\sqrt{ 3 }-7\sqrt{ 6 } \\&\approx1.90613\end{align*}$