a,0.425*54
b,270:10.8
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a) \(\left(2x-3\right)^4=5^4\)
\(\Rightarrow\left[{}\begin{matrix}2x-3=5\\2x-3=-5\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}2x=8\\2x=-2\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{8}{2}=4\\x=-\dfrac{2}{2}=-1\end{matrix}\right.\)
b) \(\left(2x-3\right)^3=-64\)
\(\Rightarrow\left(2x-3\right)^3=\left(-4\right)^3\)
\(\Rightarrow2x-3=-4\)
\(\Rightarrow2x=-1\)
\(\Rightarrow x=-\dfrac{1}{2}\)
a/
\(\left(2x-3\right)^4=5^4\\ \Leftrightarrow\left|2x-3\right|=5\\ \Leftrightarrow\left[{}\begin{matrix}2x-3=5\\2x-3=-5\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}2x=8\\2x=-2\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=4\\x=-1\end{matrix}\right.\)
Vậy...
b/ 2x-3=-64
<=>2x = -61
<=> x = -61/2
\(4^{10}\cdot8^{15}\)
\(=\left(2^2\right)^{10}\cdot\left(2^3\right)^{15}\)
\(=2^{20}\cdot2^{45}\)
\(=2^{20+45}\)
\(=2^{65}\)
\(A=\frac{20\cdot4^{14}\cdot9^9-4\cdot9^{10}\cdot8^9}{40\cdot2^6\cdot6^{19}-7\cdot2^{29}\cdot27^6}\)
\(=\frac{2^2\cdot5\cdot2^{28}\cdot3^{18}-2^2\cdot3^{20}\cdot2^{27}}{2^3\cdot5\cdot2^6\cdot2^{19}\cdot3^{19}-7\cdot2^{29}\cdot3^{18}}\)
\(=\frac{2^{30}\cdot3^{18}\cdot5-2^{29}\cdot3^{20}}{2^{28}\cdot3^{19}\cdot5-2^{29}\cdot3^{18}\cdot7}\)
\(=\frac{2^{29}\cdot3^{18}\left(2\cdot5-3^2\right)}{2^{28}\cdot3^{18}\cdot\left(3\cdot5-2\cdot7\right)}\)
\(=\frac{2^{29}\cdot3^{18}}{2^{28}\cdot3^{18}}=2\)
Vậy : \(A=2\)
`B=45a+79b+30a-54b`
`=75a+25b`
`=25(3a+b)`
`=25.2021`
`=50525`
a.22,95
b,216
chúc hok tốt
a = 22.95
b , = 25