A= ($\sqrt[]{6}$ + $\sqrt[]{10}$) ($\sqrt[]{4-\sqrt[]{15}}$)
= ($\sqrt[]{2}$ ($\sqrt[]{3}$ + $\sqrt[]{5}$) ) ($\sqrt[]{4-\sqrt[]{15}}$ )
<=> 2A = 2 ($\sqrt[]{3}$ + $\sqrt[]{5}$) ($\sqrt[]{8-2\sqrt[]{15}}$ )
= 2 ($\sqrt[]{3}$ + $\sqrt[]{5}$) ( $\sqrt[]{3+5-2\sqrt[]{3}\sqrt[]{5}}$ )
= 2 ($\sqrt[]{3}$ + $\sqrt[]{5}$) ($\sqrt[]{(\sqrt[]{3}-\sqrt[]{5})^{2}}$ )
= 2 ($\sqrt[]{3}$ + $\sqrt[]{5}$) ( $\sqrt[]{5}$-$\sqrt[]{3}$ ) = 2 (5-3) = 4
=> A=2
