Tính:
a)\(\dfrac{8^{20}.4^{10}}{16^{21}}\)
\(=\dfrac{\left(2^3\right)^{20}.\left(2^2\right)^{10}}{\left(2^4\right)^{21}}\)
\(=\dfrac{2^{60}.2^{20}}{2^{84}}\)
\(=\dfrac{2^{80}}{2^{84}}\)
\(=2^{80-84}\)
\(=2^{-4}\)
\(=\dfrac{1}{16}\)
Đúng 0
Bình luận (0)
Tính:
b)\(\dfrac{8^{20}+4^{20}}{4^{25}+64^5}\)
\(=\dfrac{\left(2^3\right)^{20}+\left(2^2\right)^{20}}{\left(2^2\right)^{25}+\left(2^6\right)^5}\)
\(=\dfrac{2^{60}+2^{20}}{2^{50}+2^{30}}\)
\(=\dfrac{2^{40}\left(2^{20}+1\right)}{2^{30}\left(2^{20}+1\right)}\)
\(=\dfrac{2^{40}}{2^{30}}\)
\(=2^{40-30}\)
\(=2^{10}\)
\(=1024\)
Đúng 0
Bình luận (0)
