Factor $18=3^{2}\times 2$. Rewrite the square root of the product $\sqrt{3^{2}\times 2}$ as the product of square roots $\sqrt{3^{2}}\sqrt{2}$. Take the square root of $3^{2}$.
Factor $98=7^{2}\times 2$. Rewrite the square root of the product $\sqrt{7^{2}\times 2}$ as the product of square roots $\sqrt{7^{2}}\sqrt{2}$. Take the square root of $7^{2}$.
Factor $8=2^{2}\times 2$. Rewrite the square root of the product $\sqrt{2^{2}\times 2}$ as the product of square roots $\sqrt{2^{2}}\sqrt{2}$. Take the square root of $2^{2}$.
$$\frac{\sqrt{2}}{6\times 2\sqrt{2}-4\sqrt{2}}$$
Multiply $6$ and $2$ to get $12$.
$$\frac{\sqrt{2}}{12\sqrt{2}-4\sqrt{2}}$$
Combine $12\sqrt{2}$ and $-4\sqrt{2}$ to get $8\sqrt{2}$.
$$\frac{\sqrt{2}}{8\sqrt{2}}$$
Rationalize the denominator of $\frac{\sqrt{2}}{8\sqrt{2}}$ by multiplying numerator and denominator by $\sqrt{2}$.
