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\(B=\left[1-\frac{1}{2}\right]\cdot\left[1-\frac{1}{3}\right]\cdot\left[1-\frac{1}{4}\right]\cdot...\cdot\left[1-\frac{1}{20}\right]\)
\(B=\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{3}{4}\cdot...\cdot\frac{19}{20}\)
\(B=\frac{1\cdot2\cdot3\cdot...\cdot19}{2\cdot3\cdot4\cdot...\cdot20}=\frac{1}{20}\)
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\(\frac{3^{10}.\left(-5\right)^{21}}{\left(-5\right)^{20}.3^{12}}=\frac{3^{10}.\left(-5\right)^{20}.\left(-5\right)}{\left(-5\right)^{20}.3^{10}.3^2}=\frac{-5}{3^2}=-\frac{5}{9}\)
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\(\frac{-5^3\cdot40\cdot4^3}{135\cdot\left(-2\right)^{14}\left(-100\right)^0}=\frac{-125\cdot2^3\cdot5\cdot\left(2^2\right)^3}{5\cdot27\cdot2^{14}\cdot1}=\frac{-125\cdot2^6}{27\cdot2^{11}}=\frac{-125}{27\cdot2^5}=\frac{-125}{864}\)
\(\frac{\left(-5\right)^3.40.4^3}{135.\left(-2\right)^{14}.\left(-100\right)^0}\)\(=\frac{\left(-5\right)^3.5.2^3.2^6}{3^3.5.2^{14}.1}\)\(=\frac{-125}{864}\)
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(2/3×x-1/3)=2/3+1/3
(2/3×x-1/3)=3/3
2/3×x=3/3+1/3
2/3×x=4/3
x=4/3:3/2
x=4/3×2/3
x=8/9
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Cảm ơn nhưng mình tìm ra đáp án rồi :
\(\frac{-1997\times1996+1}{\left(-1995\right)\left(-1997\right)+1996}=\frac{-1997\times\left(1995+1\right)+1}{1995\times1997+1996}=\frac{-1997\times1995-1997+1}{1995\times1997+1996}=\frac{-1997\times1995-1996}{1995\times1997+1996}=\frac{-\left(1997\times1995+1996\right)}{1995\times1997+1996}=-1\)
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giải hộ mk vs
\(\frac{\left(-30\right)\left(-5\right)\cdot3}{6\cdot25\cdot8}\Leftrightarrow\frac{30\cdot5\cdot3}{6\cdot25\cdot8}\)
\(\Rightarrow\frac{6\cdot5\cdot5\cdot3}{6\cdot5\cdot5\cdot8}=\frac{3}{8}\)