Question 943115
Distribute the second term,
{{{(2-sqrt(6))(1+sqrt(6))=(2-sqrt(6))+(2-sqrt(6))sqrt(6)}}}
{{{(2-sqrt(6))(1+sqrt(6))=2-sqrt(6)+2sqrt(6)-6}}}
{{{(2-sqrt(6))(1+sqrt(6))=2-sqrt(6)+2sqrt(6)-6}}}
{{{(2-sqrt(6))(1+sqrt(6))=-4+sqrt(6)}}}