[tex]9 \sqrt{2} ( 3 \sqrt{10} - (6 \sqrt{10} -2 \sqrt{5} ( 6 \sqrt{2} - 4 \sqrt{2} ))[/tex]
[tex]9 \sqrt{2} ( 3 \sqrt{10} - (6 \sqrt{10} -2 \sqrt{5} *2 \sqrt{2} )
[/tex]
[tex]9 \sqrt{2} ( 3 \sqrt{10} - 2 \sqrt{10}) [/tex]
[tex]9 \sqrt{2} * \sqrt{10} [/tex]
[tex]9 \sqrt{20} = 18 \sqrt{5} [/tex]