Odpowiedź:
[tex]\sqrt{20}+\sqrt{80}=\sqrt{180}\\\\\sqrt{4\cdot5}+\sqrt{16\cdot5}=\sqrt{36\cdot5}\\\\2\sqrt{5}+4\sqrt{5}=6\sqrt{5}\\\\6\sqrt{5}=6\sqrt{5}\\\\L=P[/tex]
