The requested page was not found, but try solving this simple math problem (no calculator).

\[\begin{array}{c}

{x^2} + {y^2} = 800\\

xy = 198\\

{\left( {x – y} \right)^2} = \: ?

\end{array}\]

\[\begin{array}{*{20}{c}}

{\left( a \right)}&{104}&{}\\

{\left( b \right)}&{204}&{}\\

{\left( c \right)}&{304}&{}\\

{\left( d \right)}&{404}&{\left( {{\rm{correct \: answer}}} \right)}\\

{\left( e \right)}&{504}&{}

\end{array}\]