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24 tháng 9 2019

\(\frac{2^{13}\cdot3^7}{4^7\cdot9^3}=\frac{2^{13}\cdot3^7}{\left[2^2\right]^7\cdot\left[3^2\right]^3}=\frac{2^{13}\cdot3^7}{2^{14}\cdot3^6}=2^{-1}\cdot3=\frac{1}{2}\cdot3=\frac{3}{2}\)

5 tháng 7 2016

a.

\(\frac{2^7\times9^3}{6^5\times8^2}=\frac{2^7\times\left(3^2\right)^3}{\left(2\times3\right)^5\times\left(2^3\right)^2}=\frac{2^7\times3^6}{2^5\times3^5\times2^6}=\frac{3}{2^4}=\frac{3}{16}\)

b.

\(\frac{6^3+3\times6^2+3^3}{-13}=\frac{\left(2\times3\right)^3+3\times\left(3\times2\right)^2+3^3}{-13}=\frac{2^3\times3^3+3\times3^2\times2^2+3^3}{-13}=\frac{8\times3^3+3^3\times4+3^3}{-13}\)\(=\frac{3^3\times\left(8+4+1\right)}{-13}=\frac{27\times13}{-13}=-27\)

c.

\(\frac{5^4\times20^4}{25^5\times4^5}=\frac{\left(5\times20\right)^4}{\left(25\times4\right)^5}=\frac{100^4}{100^5}=\frac{1}{100}\)

d.

\(\left(\frac{5^4-5^3}{125^4}\right)=\frac{5^3\times\left(5-1\right)}{\left(5^3\right)^4}=\frac{5^3\times4}{5^{12}}=\frac{4}{5^9}\)

5 tháng 7 2016

a)\(\frac{2^7.9^3}{6^5.8^2}=\frac{2^7.\left(3^2\right)^3}{2^5.3^5.\left(2^3\right)^2}=\frac{2^7.3^6}{2^5.3^5.2^6}=\frac{3}{2^4}\)

b)\(\frac{6^3+3.6^2+3^3}{-13}=\frac{6.6^2+3.6^2+3^3}{-13}=\frac{6^2.\left(6+3\right)+3^3}{-13}=\frac{6^2.9+3^3}{-13}=\frac{6^2.3^2+3.3^2}{-13}=\frac{3^2.\left(6^2+3\right)}{-13}=\frac{3^2.39}{-13}=3^2.\left(-3\right)=-27\)

c)\(\frac{5^4.20^4}{25^5.4^5}=\frac{100^4}{100^5}=\frac{1}{100}\)

 

 

23 tháng 2 2019

\(a,=\frac{2^7\cdot\left(3^2\right)^3}{2^5\cdot3^5\cdot2^3}=\frac{2^7\cdot3^6}{2^8\cdot3^5}=\frac{3}{2}\)

câu a)

\(=\frac{2^7\times\left(3^2\right)^3}{2^5\times3^5\times2^3}=\frac{2^7\times3^6}{2^8\times3^5}=\frac{3}{2}\)

13 tháng 7 2019

a)\(=\frac{3^7}{2^2.3^4}=\frac{3^3}{2^2}=\frac{27}{4}\)

b)\(=\frac{2^{20}+2^{12}}{2^{10}+2^{18}}=\frac{2^{12}\left(2^8+1\right)}{2^{10}\left(1+2^8\right)}=\frac{2^{12}}{2^{10}}=2^2=4\)

20 tháng 7 2017

-46/24 5

BÀI 1

\(\frac{2^7.9^3}{6^5.8^2}=\frac{2^7.\left(3^2\right)^3}{\left(2.3\right)^5.\left(2^3\right)^2}=\frac{2^7.3^6}{2^5.3^5.2^6}=\frac{3}{2^4}=\frac{3}{16}.\)

bài 2

a)           \(\frac{1}{2}-\frac{1}{3}+\frac{1}{12}=\frac{6}{12}-\frac{4}{12}+\frac{1}{12}=\frac{3}{12}=\frac{1}{4}\)

b)          \(\frac{9^9.27^4}{3^8.81^5}=\frac{\left(3^2\right)^9.\left(3^3\right)^4}{3^8.\left(3^4\right)^5}=\frac{3^{18}.3^{12}}{3^8.3^{20}}=\frac{3^{30}}{3^{28}}=3^2=9\)

Study well 

23 tháng 8 2019

Bài 1: \(\frac{2^7.9^3}{6^5.8^2}=\frac{2^7.3^6}{2^5.3^5.2^6}=\frac{3}{2^4}=\frac{3}{16}\)

Bài 2: 

a)\(\frac{1}{2}-\frac{1}{3}+\frac{1}{12}=\frac{6}{12}-\frac{4}{12}+\frac{1}{12}=\frac{6-4+1}{12}=\frac{1}{4}\)

b)\(\frac{9^9.27^4}{3^8.81^5}=\frac{9^9.3^{12}}{3^8.9^{10}}=\frac{3^4}{9}=\frac{3^4}{3^2}=3^2=9\)

13 tháng 3 2019

\(A=\frac{1}{3\cdot5}+\frac{1}{5\cdot7}+\frac{1}{7\cdot9}+...+\frac{1}{97\cdot99}-\frac{5}{4}\cdot\frac{13}{99}+\frac{5}{99}\cdot\frac{1}{4}\)

\(A=\frac{1}{2}\left(\frac{2}{3\cdot5}+\frac{2}{5\cdot7}+...+\frac{2}{97\cdot99}\right)-\frac{13}{4}\cdot\frac{5}{99}+\frac{5}{99}\cdot\frac{1}{4}\)

\(A=\frac{1}{2}\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{97}-\frac{1}{99}\right)-\frac{5}{99}\cdot\left(\frac{13}{4}-\frac{1}{4}\right)\)

\(A=\frac{1}{2}\left(\frac{1}{3}-\frac{1}{99}\right)-\frac{5}{99}\cdot3\)

\(A=\frac{1}{2}\cdot\frac{32}{99}-\frac{5}{33}\)

\(A=\frac{16}{99}-\frac{5}{33}=\frac{1}{99}\)

13 tháng 3 2019

3/\(7a+b=0\Rightarrow b=-7a\)

\(f\left(x\right)=ax^2-7ax+c\).Ta có: \(f\left(10\right)=100a-70a+c=30a+c\)

\(f\left(-3\right)=30a+c\).Nhân theo vế ta có đpcm:

\(f\left(10\right).f\left(-3\right)=\left(30a+c\right)^2\ge0\) (đúng)

20 tháng 4 2018

\(B=\frac{3^9-2^3\cdot3^7+2^{10}\cdot3^2-2^{13}}{3^{10}-2^2\cdot3^7+2^{10}\cdot3^3-2^{12}}\)

\(B=\frac{1-2\cdot1+1\cdot1-2}{3-1\cdot1+1\cdot3-1}\)

\(B=\frac{1-2+1-2}{3-1+3-1}\)

\(B=\frac{-1+\left(-1\right)}{2+2}\)

\(B=\frac{-2}{4}\)

\(\Rightarrow B=\frac{-1}{2}\)

31 tháng 8 2016

\(B=\frac{0,6-\frac{3}{11}+\frac{3}{13}}{1,4-\frac{7}{11}+\frac{7}{13}}-\frac{\frac{1}{3}-0,25+\frac{1}{5}}{1\frac{1}{6}-0,875+0,7}\) 

\(B=\frac{\frac{3}{5}-\frac{3}{11}+\frac{3}{13}}{\frac{7}{5}-\frac{7}{11}+\frac{7}{13}}-\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\)

\(B=\frac{3\left(\frac{1}{5}-\frac{1}{11}+\frac{1}{13}\right)}{5\left(\frac{1}{5}-\frac{1}{11}+\frac{1}{13}\right)}-\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{7\left(\frac{1}{6}-\frac{1}{8}+\frac{1}{10}\right)}\)

\(B=\frac{3}{5}-\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{7.\frac{1}{2}\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{5}\right)}\)

\(B=\frac{3}{5}-\frac{2}{7}=\frac{11}{35}\)