a, \(\dfrac{\left(2-\sqrt{2}\right).\sqrt{2}}{\sqrt{2}.\sqrt{2}}\)=\(\dfrac{2\sqrt{2}-2}{2}\)=\(\sqrt{2}-1\)
b, \(\dfrac{\left(x-49\right)\left(\sqrt{x}+7\right)}{\left(\sqrt{x}-7\right)\left(\sqrt{x}+7\right)}=\dfrac{\left(\sqrt{x}+7\right)\left(x-49\right)}{x-49}=\sqrt{x}+7\)