Răspuns :
4 rad 18 - 4 rad 12 =
= 4 ( rad 18 - rad 12 ) =
= 4 ( 3 rad 2 - 2 rad 3 )
= 4 ( rad 18 - rad 12 ) =
= 4 ( 3 rad 2 - 2 rad 3 )
[tex]\it 4\sqrt{18} -4\sqrt{12} = 4(\sqrt{9\cdot2} - \sqrt{4\cdot3}) = 4(3\sqrt2 - 2\sqrt3)[/tex]