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a: \(=\dfrac{-3^{10}\cdot5^{21}}{5^{20}\cdot3^{12}}=-\dfrac{5}{9}\)
b: \(=\dfrac{-11^5\cdot13^7}{11^5\cdot13^8}=\dfrac{-1}{13}\)
c: \(=2^{10}\cdot3^{10}-2^{10}\cdot3^9=2^{10}\cdot3^9\cdot\left(3-1\right)=2^{11}\cdot3^9\)
a) \(4^n=4096\Rightarrow4^n=4^6\Rightarrow n=6\)
b) \(5^n=15625\Rightarrow5^n=5^6\Rightarrow n=6\)
c) \(6^{n+3}=216\Rightarrow6^{n+3}=6^3\Rightarrow n+3=3\Rightarrow n=0\)
d) \(x^2=x^3\Rightarrow x^3-x^2=0\Rightarrow x^2\left(x-1\right)=0\Rightarrow\left[{}\begin{matrix}x=0\\x-1=0\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)
e) \(3^{x-1}=27\Rightarrow3^{x-1}=3^3\Rightarrow x-1=3\Rightarrow x=4\)
f) \(3^{x+1}=9\Rightarrow3^{x+1}=3^2\Rightarrow x+1=2\Rightarrow x=1\)
g) \(6^{x+1}=36\Rightarrow6^{x+1}=6^2\Rightarrow x+1=2\Rightarrow x=1\)
h) \(3^{2x+1}=27\Rightarrow3^{2x+1}=3^3\Rightarrow2x+1=3\Rightarrow2x=2\Rightarrow x=1\)
i) \(x^{50}=x\Rightarrow x^{50}-x=0\Rightarrow x\left(x^{49}-1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x^{49}-1=0\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=0\\x^{49}=1=1^{49}\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)
4n = 4096
4n = 212
n = 12
5n = 15625
5n = 56
n = 6
6n+3 = 216
6n+3 = 23.33
6n+3 = 63
n + 3 = 3
Bài 1 :
\(M=\dfrac{30-2^{20}}{2^{18}}=\dfrac{2.15-2^{20}}{2^{18}}=\dfrac{15}{2^{17}}-2^2=\dfrac{15}{2^{17}}-4< 0\left(\dfrac{15}{2^{17}}< 1\right)\)
\(N=\dfrac{3^5}{1^{2021}+2^3}=\dfrac{3^5}{9}=\dfrac{3^5}{3^2}=3^3=27\)
\(\Rightarrow M< N\)
Bài 3 :
a) \(t^2+5t-8\) khi \(t=2\)
\(=5^2+2.5-8\)
\(=25+10-8\)
\(=27\)
b) \(\left(a+b\right)^2-\left(b-a\right)^3+2021\left(1\right)\)
\(\left\{{}\begin{matrix}a=5\\b=a+1=6\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}a+b=11\\b-a=1\end{matrix}\right.\)
\(\left(1\right)=11^2-1^3+2021=121-1+2021=2141\)
c) \(x^3-3x^2y+3xy^2-y^3=\left(x-y\right)^3\left(1\right)\)
\(\left\{{}\begin{matrix}x=3\\y=2\end{matrix}\right.\) \(\Rightarrow x-y=1\)
\(\left(1\right)=1^3=1\)
1.
a) \(3^2\cdot2^5-\left(3\cdot6^2-x\right)=120\\ 9\cdot32-\left(3\cdot36-x\right)=120\\ 288-\left(108-x\right)=120\\ 288-108+x=120\\ 180+x=120\\ \Rightarrow x=-60\)
Vậy x = -60
b) \(\left(x+3\right)\cdot2^3-2^2\cdot5=2^2\cdot3^5\\ \left(x+3\right)\cdot8-4\cdot5=4\cdot243\\ \left(x+3\right)\cdot8-20=972\\ \Rightarrow8\left(x+3\right)=992\\ \Rightarrow x+3=124\\ \Rightarrow x=121\)
Vậy x = 121
2.
a) \(5^{x-1}-13=612\\ \Rightarrow5^{x-1}=625=5^3\\ \Rightarrow x-1=3\\ \Rightarrow x=4\)
Vậy x = 4
b) \(5^x\cdot5^3=125\\ 5^{x+3}=5^3\\ \Rightarrow x+3=3\\ \Rightarrow x=0\)
Vậy x = 0
`#3107.101107`
`n^3 = 5^3`
`=> n = 5`
Vậy, `n = 5.`
N mũ 3=5mũ 3=N=5=>n=5