$2\sqrt{3}+\ \sqrt{3}$  is equal to 

 $\sqrt{10}\ \times\sqrt{5}$  is equal to

The number obtained on rationalizing the denominator of  $\frac{1}{\sqrt{7}-2}$  is

 $\frac{1}{\sqrt{9}-\sqrt{8}}$  is equal to

After rationalize the denominator of  $\frac{7}{3\sqrt{3}-2\sqrt{2}}$ , we get the denominator as