Un număr negativ la o putere para va deveni un număr pozitiv.
[tex]x=3\sqrt{2} -5\sqrt{2} =-2\sqrt{2}[/tex]
[tex]\implies x^2=(-2\sqrt{2} )^2=2^2\sqrt{2} ^2=4\cdot2=8[/tex]
[tex]x=7\sqrt{3} -3\sqrt{3} =4\sqrt{3}[/tex]
[tex]\implies x^2=(4\sqrt{3} )^2=4^2\sqrt{3} ^2=16\cdot3=48[/tex]
[tex]x=-4\sqrt{5} -\sqrt{5} =-5\sqrt{5}[/tex]
[tex]\implies x^2=(-5\sqrt{5} )^2=5^2\sqrt{5} ^2=25\cdot5=125[/tex]
[tex]x=5\sqrt{24} -2\sqrt{54} =5\cdot2\sqrt{6} -2\cdot3\sqrt{6}[/tex]
[tex]x=10\sqrt{6} -6\sqrt{6} =4\sqrt{6}[/tex]
[tex]\implies x^2=(4\sqrt{6} )^2=4^2\sqrt{6} ^2=16\cdot6=96[/tex]
[tex]x=10\sqrt{28} -7\sqrt{63} =10\cdot2\sqrt{7} -7\cdot3\sqrt{7}[/tex]
[tex]x=20\sqrt{7} -21\sqrt{7} =-\sqrt{7}[/tex]
[tex]\implies x^2=(-\sqrt{7} )^2=\sqrt{7} ^2=7[/tex]
[tex]x=7\sqrt{80} -10\sqrt{45}=7\cdot4\sqrt{5} -10\cdot3\sqrt{5}[/tex]
[tex]x=28\sqrt{5} -30\sqrt{5} =-2\sqrt{5}[/tex]
[tex]\implies x^2=(-2\sqrt{5} )^2=2^2\sqrt{5} ^2=4\cdot5=20[/tex]
