Step-by-step explanation:
[tex] \frac{1}{{28}^{2}} \\ \\ = ( {28})^{ - 2} \\ \\ = ( {4 \times 7})^{ - 2} \\ \\ = {4}^{ - 2} . {7}^{ - 2} \\ \\ thus \\ \\ \huge \red{ \boxed{ \therefore \frac{1}{{28}^{2}} = {4}^{ - 2} . {7}^{ - 2} }}\\ [/tex]
