Recognize that "( ) over 2^3" means ( ) • 2^-3. Use the rule of exponents
.. (a^b)^c = a^(b•c)
= 2^-16•5^10•19^-2 • 5^-8*2^-12 • 2^28
Now, you can use the rule of exponents
.. (a^b)*(a^c) = a^(b+c)
= 2^(-16 -12 +28) • 5^(10 -8) • 19^-2
= 5^2 • 19^-2
= 5^2 / 19^2
= 25/361