\(\left(\sqrt{2}+1\right)^3-\left(\sqrt{2}-1\right)^3\)
= \(\left(\sqrt{2}+1-\sqrt{2}+1\right)\left[\left(\sqrt{2}+1\right)^2+\left(\sqrt{2}+1\right)\left(\sqrt{2}-1\right)+\left(\sqrt{2}-1\right)^2\right]\)
= 2\(\left[3+2\sqrt{2}+2-1+2-2\sqrt{2}+1\right]\)
= 2.7 = 14