Rút gọn :
A = \(\dfrac{9^{14}.25^6.8^7}{18^{12}.625^3.24^3}\)
Rút gọn phân số : \(\frac{9^{14}.25^5.8^7}{18^{12}.625^3.24^3}\)
\(\frac{9^{14}\cdot25^5\cdot8^7}{18^{12}\cdot625^3\cdot24^3}=\frac{\left(3^2\right)^{14}\cdot\left(5^2\right)^5\cdot\left(2^3\right)^7}{\left(3^2\cdot2\right)^{12}\cdot\left(5^4\right)^3\cdot\left(3\cdot2^3\right)^3}\)
\(=\frac{3^{28}\cdot5^{10}\cdot2^{21}}{3^{24}\cdot2^{12}\cdot5^{12}\cdot3^3\cdot2^9}=\frac{3^{28}\cdot5^{10}\cdot2^{21}}{3^{25}\cdot5^{12}\cdot2^{21}}=\frac{3^3}{5^2}=\frac{27}{25}\)
Rút gọn: \(A=\frac{9^{14}.25^5.8^7}{18^{12}.625^3.24^3}\)
\(\frac{9^{14}}{18^{12}}.\frac{25^5}{625^3}.\frac{8^7}{24^3}\)
\(=\frac{9^{14}}{\left(9.2\right)^{12}}.\frac{25^5}{25^6}.\frac{8^7}{\left(8.3\right)^3}\)
\(=\frac{9^{14}}{9^{12}.2^{12}}.\frac{1}{25}.\frac{8^7}{8^3.3^3}\)
\(=\frac{9^2}{2^{12}}.\frac{1}{25}.\frac{8^4}{3^3}\)
\(=\frac{81}{4096}.\frac{1}{25}.\frac{4096}{27}\)
\(=\frac{81}{4096}.\frac{4096}{27}.\frac{1}{24}=3.\frac{1}{24}=\frac{3}{24}\)
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trả lời
A=3/24
suy ra A=1/8
Rút gọn phân số sau
\(\frac{9^{14}.225^5.8^7}{18^{12}.625^3.24^3}\)
\(\frac{9^{14}.225^5.8^7}{18^{12}.625^3.24^3}=\frac{\left(3^2\right)^{14}.\left(3^2.5^2\right)^5.\left(2^3\right)^7}{\left(3^2.2\right)^{12}.\left(5^4\right)^3.\left(3.2^3\right)^3}=\frac{3^{28}.3^{10}.5^{10}.2^{21}}{3^{24}.2^{12}.5^{12}.3^3.2^9}=\frac{3^{38}.5^{10}.2^{21}}{3^{27}.2^{21}.5^{12}}=\frac{3^{11}}{5^2}\)
a) Tìm số tự nhiên n thoả mãn \(2^{2n-1}+4^{n+2}=264\)
b) Tính giá trị P = \(\frac{9^{14}.25^6.8^7}{18^{12}.625^3.24^3}\)
a)\(2^{2n-1}+4^{n+2}=264\)
\(264=2^3\cdot3\cdot11\)
\(2^3=2^{\left(3+1\right)\div2}=2^2\Rightarrow n=2\)
\(4^{n+2}=264-2^3=256\)
\(256=4^4=4^{4-2}=4^2\Rightarrow n=2\)
vậy \(n=2\)
b) \(P=\frac{9^{14}\cdot25^6\cdot8^7}{18^{12}\cdot625^3\cdot24^3}\)
\(P=\frac{9^{14}\cdot25^6\cdot8^7}{18^{12}\cdot25^6\cdot25^6\cdot24^3}\)
\(P=\frac{9^{14}\cdot8^7}{18^{12}\cdot24^3}=3\)
1. Tính
a) \(A=\frac{9^{14}.25^5.8^7}{^{18^{12}.625^3.24^3}}\)
1, Rút gọn
\(\frac{374}{506}\); \(\frac{3600-75}{8400-175}\); \(\frac{9^{14}.25^5.8^7}{18^{12}.625^3.24^3}\); \(\frac{2^{10}.3^{10}-2^{10}.3^9}{2^9.3^{10}}\)
2, Rút gọn 1 cách nhanh nhất
\(\frac{1989.1990+3978}{1992.1991-3984}\)
tính
20112 - ( 304 ++ 2012 ) + ( 2013 + 304)
\(\frac{9^{14}.25^5.8^7}{18^{12}.625^3.24^3}\)
20112-(304+2012)+(2013+304)
=20112-304-2012+2013+304
=20112+(-2012+2013)+(-304+304)
=20112+1+0=20113
\(\frac{9^{14}.25^5.8^7}{18^{12}.625^3.24^3}=\frac{\left(3^2\right)^{14}.25^5.\left(2^3\right)^7}{2^{12}.\left(3^2\right)^{12}.\left(25^2\right)^3.\left(2^3\right)^3.3^3}=\)\(\frac{3^{28}.25^5.2^{21}}{2^{12}.2^9.3^{24}.3^3.25^6}=\frac{3^{28}.25^5.2^{21}}{2^{21}.3^{27}.25^6}\)\(=\frac{3}{25}\)
1. Rút gọn phân số
\(\dfrac{\text{9^{14}. 25^5. 8^7}}{\left(-18\right)^{12}.625^3.24^3}\)
2. Cho \(\dfrac{23n^2-1}{35}\in Z\)
Chứng minh các phân số sau tối giản: \(\dfrac{n}{5}\); \(\dfrac{n}{7}\)
Bài 1:
\(=\dfrac{3^{28}\cdot5^{10}\cdot2^{21}}{3^{24}\cdot2^{12}\cdot5^{12}\cdot3^3\cdot2^9}=\dfrac{3}{5^2}=\dfrac{3}{25}\)
Bài 1: Rút gọn phân số
\(\frac{9^{14}.25^5.8^7}{18^{12}.625^3.24^3}\)
Bài 2:cho biểu thức A=\(\frac{8}{n+1}\)(n thuộc Z)
a) Tìm điều kiện để A là phân số
b)Tìm n để A có giá trị là số nguyên
các bạn giúp mình nha!