${({6^2})^2} \times {(\frac{1}{4})^3} = {6^4} \times {({2^{ - 2}})^3} = {(2 \times 3)^4} \times {2^{ - 6}} = {2^4} \times {3^4} \times {2^{ - 6}} = {2^{ - 2}} \times {3^4}$ ${2^{ - 2}} \times {3^4} = {2^x} \times {3^y} \Rightarrow \left. {\begin{array}{*{20}{c}}  {x =  - 2} \\   {y = 4} \end{array}} \right\} \Rightarrow x + y = ( - 2) + ( + 4) =  + 2$