The distance between the lines ${(\mathrm{x}+7\mathrm{y})}^2+4\sqrt{2}(\mathrm{x}+7\mathrm{y})-42=0$ is__________

${(\mathrm{x}+7\mathrm{y})}^2+4\sqrt{2}(\mathrm{x}+7\mathrm{y})-42=0$

or ${(\mathrm{x}+7\mathrm{y})}^2+7\sqrt{2}(\mathrm{x}+7\mathrm{y})-3\sqrt{2}(\mathrm{x}+7)-42=0$

or $(\mathrm{x}+7\mathrm{y})[\mathrm{x}+7\mathrm{y}+7\sqrt{2}]-3\sqrt{2}(\mathrm{x}+7\mathrm{y}+7\sqrt{2})=0$

or $(\mathrm{x}+7\mathrm{y}+7\sqrt{2})(\mathrm{x}+7\mathrm{y}-3\sqrt{2})=0$

or $\mathrm{x}+7\mathrm{y}+7\sqrt{2}=0$ and $\mathrm{x}+7\mathrm{y}-3\sqrt{2}=0$

or $\mathrm{d}=|\frac{7\sqrt{2}+3\sqrt{2}}{\sqrt{1+49}}|=\frac{10\sqrt{2}}{\sqrt{50}}=2$