bài 1:tinh rút gọn:
a> b> \(\frac{9^{14}.25^5.8^7.75}{18^{12}.625^3.24^3}\)
\(\frac{2^3.3^3.5^3.7.8}{3.2^4.5^3.14}\)
bài 2:chứng minh rằng 31999-71997 chia hết cho 5
help me
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\(\frac{2^3.3^3.5^3.7.8}{3.2^4.5^3.14}=\frac{2^3.3^3.5^3.7.2^3}{3.2^4.5^3.2.7}\)
\(=\frac{2^6.3^3.5^3.7}{2^5.3.5^3.7}=\frac{2.3^2.1.1}{1.1.1.1}=2.3^2\)
\(=2.9=18\)
\(\frac{2^3.3^3.5^3.7.8}{3.2^4.5^3.14}=\frac{1.3^2.1.1.8}{1.2.1.2}=\frac{3.3.4}{2.1}=\frac{3.3.2}{1}=18\)
\(\frac{2^3.3^3.5^3.7.8}{3.2^4.5^3.14}\)mk viết như vầy bn cố gắng hiểu nhé:.
23.33.53.7.8/ 3.24.53.14
= 23.33.53.7.8/3.24.53.7.2
=23.33.53.8/3.24.53.2
=23.33.53.23/24.2.53
= 23.23.33.53/ 24.2.53
= 26. 33.53/ 25. 53
= 25.2.33.53/25.53
= 2.33/1
= 2. 27/1
= 54/1 = 54
Thế nha bn, chúc bn học tốt!
a) \(\dfrac{2^4\cdot5^2\cdot7}{2^3\cdot5\cdot7^2\cdot11}=\dfrac{2^3\cdot5\cdot10\cdot7}{2^3\cdot5\cdot7\cdot77}=\dfrac{10}{77}\)
\(\dfrac{2^3\cdot3^3\cdot5^3\cdot7\cdot8}{3\cdot2^4\cdot5^3\cdot14}=\dfrac{2^3\cdot3\cdot5^3\cdot7\cdot3^2\cdot8}{3\cdot2^3\cdot2\cdot5^3\cdot14}=\dfrac{7\cdot3^2\cdot8}{2\cdot14}=\dfrac{63\cdot8}{2\cdot14}=18=\dfrac{1386}{77}\)
\(\frac{9^{14}\cdot25^5\cdot8^7}{18^{12}\cdot625^3\cdot24^3}=\frac{\left(3^2\right)^{14}\cdot\left(5^2\right)^5\cdot\left(2^3\right)^7}{\left(3^2\cdot2\right)^{12}\cdot\left(5^4\right)^3\cdot\left(3\cdot2^3\right)^3}\)
\(=\frac{3^{28}\cdot5^{10}\cdot2^{21}}{3^{24}\cdot2^{12}\cdot5^{12}\cdot3^3\cdot2^9}=\frac{3^{28}\cdot5^{10}\cdot2^{21}}{3^{25}\cdot5^{12}\cdot2^{21}}=\frac{3^3}{5^2}=\frac{27}{25}\)
\(\frac{9^{14}}{18^{12}}.\frac{25^5}{625^3}.\frac{8^7}{24^3}\)
\(=\frac{9^{14}}{\left(9.2\right)^{12}}.\frac{25^5}{25^6}.\frac{8^7}{\left(8.3\right)^3}\)
\(=\frac{9^{14}}{9^{12}.2^{12}}.\frac{1}{25}.\frac{8^7}{8^3.3^3}\)
\(=\frac{9^2}{2^{12}}.\frac{1}{25}.\frac{8^4}{3^3}\)
\(=\frac{81}{4096}.\frac{1}{25}.\frac{4096}{27}\)
\(=\frac{81}{4096}.\frac{4096}{27}.\frac{1}{24}=3.\frac{1}{24}=\frac{3}{24}\)
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