Verified answer

[tex]\displaystyle\bf\\1)\\\\0,2\sqrt{676} +\sqrt{23,04} =0,2\sqrt{26^{2} } +\sqrt{4,8^{2} } =0,2\cdot 26+4,8=\\\\=5,2+4,8=10\\\\\\2)\\\\\sqrt{961+2\cdot 31\cdot 47+2209} =\sqrt{31^{2} +2\cdot 31\cdot 47+47^{2} } =\\\\=\sqrt{(31+47)^{2} } =\sqrt{78^{2} } =78[/tex]