Answer :
[tex]\sqrt{126}= 3\sqrt{14} \\ \\ \sqrt{56}=2\sqrt{14} \\ \\ \\ \sqrt{126}+ \sqrt{56}= 3\sqrt{14}+2\sqrt{14}= 5\sqrt{14}[/tex]
[tex]\sqrt{126}+\sqrt{56}=\sqrt{9\times14}+\sqrt{4\times14}=\sqrt9\times\sqrt{14}+\sqrt4\times\sqrt{14}\\\\=3\sqrt{14}+2\sqrt{14}=5\sqrt{14}[/tex]
