Răspuns :
[tex]a = \sqrt{6}( \sqrt{54} + \sqrt{216}) \\ \\ a = \sqrt{6}(3 \sqrt{6} + 6 \sqrt{6}) \\ \\ a = \sqrt{6} \times 9 \sqrt{6} \\ \\ a = 9 \sqrt{6 \times 6} \\ \\ a = 9 \sqrt{36} \\ \\ a = 9 \times 6 \\ \\ a = 54 \: \: (F) [/tex]