Question

Tính :

a)\(\dfrac{8^{20}.4^{10}}{16^{21}}\)

b)\(\dfrac{8^{20}+4^{20}}{4^{25}+64^5}\)

Answer 1

Tính:

a)\(\dfrac{8^{20}.4^{10}}{16^{21}}\)

\(=\dfrac{\left(2^3\right)^{20}.\left(2^2\right)^{10}}{\left(2^4\right)^{21}}\)

\(=\dfrac{2^{60}.2^{20}}{2^{84}}\)

\(=\dfrac{2^{80}}{2^{84}}\)

\(=2^{80-84}\)

\(=2^{-4}\)

\(=\dfrac{1}{16}\)

Answer 2

Tính:

b)\(\dfrac{8^{20}+4^{20}}{4^{25}+64^5}\)

\(=\dfrac{\left(2^3\right)^{20}+\left(2^2\right)^{20}}{\left(2^2\right)^{25}+\left(2^6\right)^5}\)

\(=\dfrac{2^{60}+2^{20}}{2^{50}+2^{30}}\)

\(=\dfrac{2^{40}\left(2^{20}+1\right)}{2^{30}\left(2^{20}+1\right)}\)

\(=\dfrac{2^{40}}{2^{30}}\)

\(=2^{40-30}\)

\(=2^{10}\)

\(=1024\)