[tex] (2^8 \times 5^{-5} \times 19^0)^{-2} \times (\dfrac{5^{-2}}{2^3})^4 \times 2^{28} = [/tex]
[tex] = 2^{-16} \times 5^{10} \times 1 \times \dfrac{5^{-8}}{2^{12}} \times 2^{28} [/tex]
[tex] = 2^{-16} \times 5^{10} \times 5^{-8} \times 2^{-12} \times 2^{28} [/tex]
[tex] = 2^{-16} \times 2^{-12} \times 2^{28} \times 5^{10} \times 5^{-8} [/tex]
[tex] = 2^{-16-12+28} \times 5^{10-8} [/tex]
[tex] = 2^{0} \times 5^{2} [/tex]
[tex] = 1 \times 25 [/tex]
[tex] = 25 [/tex]
