Đáp án:
1
Giải thích các bước giải:
d) $\dfrac{1}{\sqrt{2}-1}-\dfrac{3\sqrt{6}-3\sqrt{10}}{\sqrt{3}-\sqrt{5}}+\dfrac{4}{\sqrt{2}}$
$=\dfrac{1}{\sqrt{2}-1}-\dfrac{3\sqrt{2}(\sqrt{3}-\sqrt{5})}{\sqrt{3}-\sqrt{5}}+2\sqrt{2}$
$=\dfrac{1}{\sqrt{2}-1}-3\sqrt{2}+2\sqrt{2}$
$=\dfrac{1}{\sqrt{2}-1}-\sqrt{2}$
$=\dfrac{1}{\sqrt{2}-1}-\dfrac{\sqrt{2}(\sqrt{2}-1)}{\sqrt{2}-1}$
$=\dfrac{1-2+\sqrt{2}}{\sqrt{2}-1}$
$=\dfrac{\sqrt{2}-1}{\sqrt{2}-1}$
$=1$
