Answer
$\dfrac{10}{\sqrt{2}-1}=10\sqrt{2}+10$
Work Step by Step
$\dfrac{10}{\sqrt{2}-1}$
Multiply the numerator and the denominator of the fraction by the conjugate of the denominator and simplify:
$\dfrac{10}{\sqrt{2}-1}=\dfrac{10}{\sqrt{2}-1}\cdot\dfrac{\sqrt{2}+1}{\sqrt{2}+1}=\dfrac{10(\sqrt{2}+1)}{(\sqrt{2})^{2}-1^{2}}=...$
$...=\dfrac{10(\sqrt{2}+1)}{2-1}=10(\sqrt{2}+1)=10\sqrt{2}+10$