\(1.B=\sqrt{4+\sqrt{10+2\sqrt{5}}}+\sqrt{4-\sqrt{10-2\sqrt{5}}}\)
\(B^2=\left(\sqrt{4+\sqrt{10+2\sqrt{5}}}+\sqrt{4-\sqrt{10-2\sqrt{5}}}\right)^2\)
\(B^2=8+2\sqrt{\left(4+\sqrt{10+2\sqrt{5}}\right)\left(4-\sqrt{10-2\sqrt{5}}\right)}\)
\(B^2=8+2\sqrt{5-2\sqrt{5}+1}=8+2\sqrt{\left(\sqrt{5}-1\right)^2}=8+2\text{ |}\sqrt{5}-1\text{ |}=6+2\sqrt{5}=5+2\sqrt{5}+1=\left(\sqrt{5}+1\right)^2\)
\(\text{ |}B\text{ |}=\text{ |}\sqrt{5}+1\text{ |}=\sqrt{5}+1\)
\(2.C=\sqrt{5\sqrt{9}+5\sqrt{48-10\sqrt{7+4\sqrt{3}}}}=\sqrt{15+5\sqrt{48-10\text{ |}\sqrt{3}+2\text{ |}}}=\sqrt{15+5\sqrt{25+2.5\sqrt{3}+3}}=\sqrt{15+5\text{ |}5+\sqrt{3}\text{ |}}=\sqrt{35+5\sqrt{3}}\)
\(3.D=\sqrt{x+2\sqrt{2x-4}}+\sqrt{x-2\sqrt{2x-4}}=\sqrt{x-2+2.\sqrt{2}.\sqrt{x-2}+2}+\sqrt{x-2-2.\sqrt{2}.\sqrt{x-2}+2}=\text{ |}\sqrt{x-2}+\sqrt{2}\text{ |}+\text{ |}\sqrt{x-2}-\sqrt{2}\text{ |}=2\sqrt{x-2}\)