mọi người ơi giúp em với ạ

B = $\sqrt{(\sqrt{3}-\sqrt{2})^{2}}$ - $\sqrt{(\sqrt{3}+\sqrt{2})^{2}}$

= |$\sqrt{3}$-$\sqrt{2}$| - |$\sqrt{3}$+$\sqrt{2}$|

= ($\sqrt{3}$-$\sqrt{2}$) - ($\sqrt{3}$+$\sqrt{2}$)

= $\sqrt{3}$ - $\sqrt{2}$ - $\sqrt{3}$ - $\sqrt{2}$

= -2$\sqrt{2}$

D = $\sqrt{3-\sqrt{5}}$ .$\sqrt{8}$ 

= $\sqrt{8.(3-\sqrt{5})}$

= $\sqrt{24-8\sqrt{5}}$

= $\sqrt{2^{2}-2.2.2\sqrt{5}+2\sqrt{5}^{2}}$

= $\sqrt{(2-2\sqrt{5})^{2}}$

= |$(2-2\sqrt{5}$|

= 2$\sqrt{5}$ -2