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XO
25 tháng 1 2020
Ta có : S = \(\frac{5.2^{30}.6^3.3^{15}-2^3.8^9.3^{17}.21}{21.2^{29}.3^{16}.4-2^{29}.\left(3^4\right)^5}=\frac{5.2^{30}.\left(2.3\right)^3.3^{15}-2^3.\left(2^3\right)^9.3^{17}.3.7}{3.7.2^{29}.3^{16}.2^2-2^{29}.3^{20}}=\frac{5.2^{33}.3^{18}-2^{30}.3^{18}.7}{3^{17}.7.2^{31}-2^{29}.3^{20}}\)
\(=\frac{2^{30}.3^{18}.\left(5.2^3-7\right)}{3^{17}.2^{29}.\left(7.2^2-3^3\right)}=2.3.33=198\)
19 tháng 3 2018
\(\Rightarrow\)C . \(\frac{2}{3}\) =\(\frac{2}{3.5}+\frac{2}{5.7}+\frac{2}{7.9}\)....+\(\frac{2}{47.49}\)
\(\Rightarrow C.\frac{2}{3}=\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+.....+\frac{1}{47}-\frac{1}{49}\)
\(\Rightarrow C=\left(\frac{1}{3}-\frac{1}{49}\right)\div\frac{2}{3}\)
\(\Rightarrow C=\frac{46}{147}\div\frac{2}{3}\)
\(\Rightarrow C=\frac{23}{49}\)
Vậy C = \(\frac{23}{49}\)
nếu đúng từ mk xin 1 chữ đúng và
16 tháng 6 2017
a) \(T=\frac{9^{14}\times25^6\times8^7}{18^{12}\times625^3\times24^3}\)
\(=\frac{\left(3^2\right)^{14}\times25^6\times\left(2^3\right)^7}{\left(2\times3^2\right)^{12}\times\left(25^2\right)^3\times\left(3\times2^3\right)^3}\)
\(=\frac{3^{28}\times25^6\times2^{21}}{2^{12}\times3^{24}\times25^6\times3^3\times2^9}\)
\(=\frac{3^{28}\times25^6\times2^{21}}{\left(2^{12}\times2^9\right)\times\left(3^{24}\times3^3\right)\times25^6}\)
\(=\frac{3^{28}\times25^6\times2^{21}}{2^{21}\times3^{27}\times25^6}=3\)
b) \(A=\frac{5\times4^{15}\times9^9-4\times3^{20}\times8^9}{5\times2^9\times6^{19}-7\times2^{29}\times27^6}\)
\(=\frac{5\times\left(2^2\right)^{15}\times\left(3^2\right)^9-2^2\times3^{20}\times\left(2^3\right)^9}{5\times2^9\times\left(2\times3\right)^{19}-7\times2^{29}\times\left(3^3\right)^6}\)
\(=\frac{5\times2^{30}\times3^{18}-2^2\times3^{20}\times2^{27}}{5\times2^9\times2^{19}\times3^{19}-7\times2^{29}\times3^{18}}\)
\(=\frac{5\times2^{30}\times3^{18}-2^{29}\times3^{20}}{5\times2^{28}\times3^{19}-7\times2^{29}\times3^{18}}\)
\(=\frac{2^{29}\times3^{18}\times\left(5\times2-3^2\right)}{2^{28}\times3^{18}\times\left(5\times3-7\times2\right)}\)
\(=\frac{2\times\left(10-9\right)}{15-14}=\frac{2\times1}{1}=2\)
14 tháng 7 2020
a) Ta có: \(\frac{16}{15}\cdot\frac{-5}{14}\cdot\frac{54}{24}\cdot\frac{56}{21}\)
\(=\frac{16}{15}\cdot\frac{-5}{14}\cdot\frac{9}{4}\cdot\frac{8}{3}\)
\(=4\cdot\frac{-1}{3}\cdot\frac{4}{7}\cdot3\)
\(=12\cdot\frac{-4}{21}=\frac{-48}{21}=\frac{-16}{7}\)
b) Ta có: \(5\cdot\frac{7}{5}=\frac{35}{5}=7\)
c) Ta có: \(\frac{1}{7}\cdot\frac{5}{9}+\frac{5}{9}\cdot\frac{1}{7}+\frac{5}{9}\cdot\frac{3}{7}\)
\(=\frac{5}{9}\left(\frac{1}{7}+\frac{1}{7}+\frac{3}{7}\right)\)
\(=\frac{5}{9}\cdot\frac{5}{7}=\frac{25}{63}\)
d) Ta có: \(4\cdot11\cdot\frac{3}{4}\cdot\frac{9}{121}\)
\(=\frac{4\cdot11\cdot3\cdot9}{4\cdot121}=\frac{27}{11}\)
e) Ta có: \(\frac{3}{4}\cdot\frac{16}{9}-\frac{7}{5}:\frac{-21}{20}\)
\(=\frac{4}{3}+\frac{4}{3}=\frac{8}{3}\)
g) Ta có: \(2\frac{1}{3}-\frac{1}{3}\cdot\left[\frac{-3}{2}+\left(\frac{2}{3}+0,4\cdot5\right)\right]\)
\(=\frac{7}{3}-\frac{1}{3}\cdot\left[\frac{-3}{2}+\frac{2}{3}+2\right]\)
\(=\frac{7}{3}-\frac{1}{3}\cdot\frac{7}{6}\)
\(=\frac{7}{3}-\frac{7}{18}=\frac{42}{18}-\frac{7}{18}=\frac{35}{18}\)
MN
27 tháng 1 2020
Ta có :
\(S=\frac{5\times2^{30}\times6^2\times3^{15}-2^3\times8^9\times3^{17}\times21}{21\times2^{29}\times3^{16}\times4-2^{29}\times\left(3^4\right)^5}\)
\(S=\frac{5\times2^{30}\times2^2\times3^2\times3^{15}-2^3\times2^{27}\times3^{17}\times3\times7}{3\times7\times2^{29}\times3^{16}\times2^2-2^{29}\times3^{20}}\)
\(S=\frac{5\times2^{32}\times3^{17}-2^{30}\times3^{18}\times7}{7\times2^{31}\times3^{17}-2^{29}\times3^{20}}\)
\(S=\frac{2^{30}\times3^{17}\times\left(5\times2^2-3\times7\right)}{2^{29}\times3^{17}\times\left(2^2\times7-3^3\right)}\)
\(S=\frac{2^{30}\times3^{17}\times\left(-1\right)}{2^{29}\times3^{17}\times1}\)
\(\Rightarrow S=-2\)
BN
27 tháng 1 2020
Ko viết đề :)
\(S=\frac{5\cdot2^{30}\cdot2^2\cdot3^2\cdot3^{15}-2^3\cdot2^{27}\cdot3^{17}\cdot3\cdot7}{3\cdot7\cdot2^{29}\cdot3^{16}\cdot2^2-2^{29}\cdot3^{20}}\)
\(=\frac{5\cdot2^{32}\cdot3^{17}-2^{30}\cdot3^{18}\cdot7}{3^{17}\cdot7\cdot2^{31}-2^{29}\cdot3^{20}}\)
\(=\frac{2^{30}\cdot3^{17}\left(5\cdot2^2-3\cdot7\right)}{2^{29}\cdot3^{17}\left(7\cdot2^2-3^3\right)}\)
\(=\frac{2\left(20-21\right)}{28-27}\)
\(=\frac{40-42}{1}=-\frac{2}{1}=-2\)
Vậy S= -2
\(B=\frac{16^5\cdot49^3}{7^5\cdot8^{21}}=\frac{\left[2^4\right]^5\cdot\left[7^2\right]^3}{7^5\cdot\left[2^3\right]^{21}}=\frac{2^{4\cdot5}\cdot7^{2\cdot3}}{7^5\cdot2^{3\cdot21}}=\frac{2^{20}\cdot7^6}{7^5\cdot2^{42}}=\frac{2^{20}\cdot7^5\cdot7}{7^5\cdot2^{20}\cdot2^{22}}=\frac{7}{2^{22}}\)
Bạn nè...Cho mik hỏi...3.21=42???