If $$\frac{{4 + 3\sqrt 3 }}{{\sqrt {7 + 4\sqrt 3 } }} = {\text{A}} + \sqrt {\text{B}} ,$$     then B - A is

Solution(By Examveda Team)

$$\eqalign{ & \frac{{4 + 3\sqrt 3 }}{{\sqrt {7 + 4\sqrt 3 } }} = {\text{A}} + \sqrt {\text{B}} \cr & \Rightarrow \sqrt {7 + 4\sqrt 3 } \cr & \Rightarrow \sqrt {{{\left( 2 \right)}^2} + {{\left( {\sqrt 3 } \right)}^2} + 2 \times 2\sqrt 3 } \cr & \Rightarrow \sqrt {{{\left( {2 + \sqrt 3 } \right)}^2}} \cr & \Rightarrow \left( {2 + \sqrt 3 } \right) \cr & \Rightarrow \frac{{4 + 3\sqrt 3 }}{{2 + \sqrt 3 }} = {\text{A}} + \sqrt {\text{B}} \cr & \Rightarrow \frac{{4 + 3\sqrt 3 }}{{2 + \sqrt 3 }} \times \frac{{2 - \sqrt 3 }}{{2 - \sqrt 3 }} = {\text{A}} + \sqrt {\text{B}} \cr & \Rightarrow \frac{{\left( {4 + 3\sqrt 3 } \right)\left( {2 - \sqrt 3 } \right)}}{{4 - 3}} = {\text{A}} + \sqrt {\text{B}} \cr & \Rightarrow 8 - 4\sqrt 3 + 6\sqrt 3 - 9 = {\text{A}} + \sqrt {\text{B}} \cr & \Rightarrow 2\sqrt 3 - 1 = {\text{A}} + \sqrt {\text{B}} \cr & {\text{A}} = - 1{\text{ and }}\sqrt {\text{B}} = 2\sqrt 3 \cr & {\text{B}} = 2\sqrt 3 \times 2\sqrt 3 = 12 \cr & {\text{B }} - {\text{ A}} = 12 - \left( { - 1} \right) = 13 \cr} $$