As per the given question,
\[1\text{ }+\text{ }3{{\left( {\scriptscriptstyle 1\!/\!{ }_2}\text{ }-\text{ }a \right)}^{2}}~\left( -1 \right)\text{ }=\text{ }0\]
\[1\text{ }-\text{ }3{{\left( {\scriptscriptstyle 1\!/\!{ }_2}\text{ }-\text{ }a \right)}^{2}}~=\text{ }0\]
