Problem:
Simplify the following radical expression: $\left(\sqrt{20}-\sqrt{78}\right)-\sqrt{139}$.
Answer:
\begin{array}{l}
 
\begin{array}{l}
 \text{Simplify the following}: \\
 \sqrt{20}-\sqrt{78}-\sqrt{139} \\
\end{array}
 \\
\hline
 
\begin{array}{l}
 \sqrt{20} \text{= }\sqrt{2^2\times 5} \text{= }2 \sqrt{5}: \\
 \fbox{$
\begin{array}{ll}
 \text{Answer:} &  \\
 \text{} & \fbox{$2 \sqrt{5}$}-\sqrt{78}-\sqrt{139} \\
\end{array}
$} \\
\end{array}
 \\
\end{array}
{'source': 'AMPS', 'file': 'amps/mathematica/algebra/simplify_radicals_w_steps/3578.txt'}