Answer
$-3-3\sqrt2$
Work Step by Step
Rationalize the denominator by multiplying $1+\sqrt{2}$ to both the numerator and the denominator to have:
$=\dfrac{3}{1-\sqrt{2}} \cdot \dfrac{1+\sqrt{2}}{1+\sqrt{2}}
\\=\dfrac{3+3\sqrt{2}}{1-2}
\\=\dfrac{3+3\sqrt{2}}{-1}
\\=-3-3\sqrt2$
