rút gọn biểu thức sau
a. \(\sqrt{\left(\sqrt{3}-1\right)^2}+\sqrt{\left(\sqrt{3}+1\right)^2}\)
b. \(\sqrt{\left(\sqrt{2}+5\right)^2}-\sqrt{\left(\sqrt{2}-5\right)^2}\)
c. \(\sqrt{7+2\sqrt{10}-\sqrt{7-2\sqrt{10}}}\)
d. \(\sqrt{8-2\sqrt{15}}-\sqrt{8+2\sqrt{15}}\)