Tính và so sánh: \(\left(5\times6\right)^2\) và \(5^2\times6^2\)
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\(\frac{\left(-0,25\right)^{-5}.9^4.\left(-2\right)^{-3}-2^{-2}.6^9}{2^9.3^6+6^6.40}\)
\(=\frac{\left(-4\right)^5.\left(3^2\right)^4.\left(-2\right)^{-3}-2^{-2}.\left(3.2\right)^9}{2^9.3^6+\left(2.3\right)^6.2^3.5}\)
\(=\frac{-\left(2^2\right)^5.3^8.\left(-2\right)^{-3}-2^{-2}.3^9.2^9}{2^9.3^6+2^6.3^6.2^3.5}\)
\(=\frac{-2^{10}3^8.\left(-2\right)^{-3}-2^7.3^9}{2^9.3^6+2^9.3^6.5}\)
\(=\frac{2^73^8.-2^7.3^9}{2^9.3^6+2^9.3^6.5}\)
\(=\frac{2^7.3^8.\left(1-3\right)}{2^9.3^6.\left(1+5\right)}\)
\(=\frac{3^2.\left(-2\right)}{2^2.6}\)
\(=\frac{-3}{4}\)
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a) \(15.4=15.\left(2.2\right)=\left(15.2\right).2=30.2=60\)
\(25.12=25.\left(2.6\right)=\left(25.2\right).6=50.6=300\)
\(125.16=125.\left(2.8\right)=\left(125.8\right).2=1000.2=2000\)
b) \(25.12=25.\left(10+2\right)=25.10+25.2=250+50=300\)
\(34.11=34.\left(10+1\right)=34.10+34.1=340+34=374\)
\(47.101=47.\left(100+1\right)=47.100+47.1=4700+47=4747\)
Chúc em học tốt!!!
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Ta có : S = \(\frac{5.2^{30}.6^3.3^{15}-2^3.8^9.3^{17}.21}{21.2^{29}.3^{16}.4-2^{29}.\left(3^4\right)^5}=\frac{5.2^{30}.\left(2.3\right)^3.3^{15}-2^3.\left(2^3\right)^9.3^{17}.3.7}{3.7.2^{29}.3^{16}.2^2-2^{29}.3^{20}}=\frac{5.2^{33}.3^{18}-2^{30}.3^{18}.7}{3^{17}.7.2^{31}-2^{29}.3^{20}}\)
\(=\frac{2^{30}.3^{18}.\left(5.2^3-7\right)}{3^{17}.2^{29}.\left(7.2^2-3^3\right)}=2.3.33=198\)
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\(\left(5\times6\right)^2\) = 302 = 900 (1)
\(5^2\times6^2\) = 25 . 36 = 900 (2)
Từ (1) và (2) ⇒ (5 . 6 )2 = 52 . 62 ( = 900)
(5.6)2 <52.62