Đáp án:
Giải thích các bước giải:
$1.$
$A=\sqrt{5-2\sqrt{6}}+\sqrt{5+2\sqrt{6}}$
$A=\sqrt{(\sqrt{3}-\sqrt{2})^2}+\sqrt{(\sqrt{3}+\sqrt{2})^2}$
$A=2\sqrt{3}$
$2.$
$x-2\sqrt{xy}+y$ với $(x\geq0 ; y\geq0 )$
$=\sqrt{x^2}-2\sqrt{x}.\sqrt{y}+\sqrt{y^2}$
$=(\sqrt{x}-\sqrt{y})^2$
$3.$
$(4+\sqrt{15}).(\sqrt{10}-\sqrt{6}).\sqrt{4-\sqrt{15}}=2$
$4\sqrt{10}-4\sqrt{6}+5\sqrt{6}-3\sqrt{10}=\dfrac{2\sqrt{2}}{\sqrt{8-2\sqrt{15}}}$
$(\sqrt{10}+\sqrt{6}).(\sqrt{5}-\sqrt{3})=2\sqrt{2}$
$5\sqrt{2}-\sqrt{30}+\sqrt{30}-3\sqrt{2}=2\sqrt{2}$
$2\sqrt{2}=2\sqrt{2}$
$2=2(TM)$
