a) \(\sqrt{\left(\sqrt{8}-3\right)^2}-\sqrt{\left(2-\sqrt{5}\right)^2}+\sqrt{\left(-5\right)^2}\)
\(=\sqrt{8}-3-2+\sqrt{5}+5\)
\(=2\sqrt{2}+\sqrt{5}\)
b) \(\sqrt{6-2\sqrt{5}}-\sqrt{6+2\sqrt{5}}\)
\(=\sqrt{\left(\sqrt{5}-1\right)^2}-\sqrt{\left(\sqrt{5}+1\right)^2}\)
\(=\sqrt{5}-1-\sqrt{5}-1=-2\)
c) \(\sqrt{3+\sqrt{5}}-\sqrt{3-\sqrt{5}}\)
\(=\sqrt{\left(\sqrt{\dfrac{5}{2}}+\sqrt{\dfrac{1}{2}}\right)^2}-\sqrt{\left(\sqrt{\dfrac{5}{2}}-\sqrt{\dfrac{1}{2}}\right)^2}\)
\(=\sqrt{\dfrac{5}{2}}+\sqrt{\dfrac{1}{2}}-\sqrt{\dfrac{5}{2}}+\sqrt{\dfrac{1}{2}}=\sqrt{2}\)