e foarte simplu, introducem factorii sub radical, apoi comparăm
[tex]\it 3\sqrt7=\sqrt{3^2\cdot7}=\sqrt{9\cdot7}=\sqrt{63}\\ \\ 7\sqrt3=\sqrt{7^2\cdot3}=\sqrt{49\cdot3}=\sqrt{147}\\ \\ \sqrt{63}<\sqrt{147}\ \Rightarrow 3\sqrt7<7\sqrt3[/tex]
