Răspuns :
[tex]\sqrt{98} = \sqrt{2\cdot 49} = \sqrt{2\cdot 7^2} = \sqrt{7^2}\cdot \sqrt2 = 7\sqrt2\\ \\ \sqrt{54} = \sqrt{2\cdot 27} = \sqrt{2\cdot 3^3} = \sqrt{2\cdot 3^2\cdot 3} = \sqrt{3^2}\cdot \sqrt{2\cdot 3} = 3\sqrt6[/tex]