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\(=\frac{9^{15}.6^{30}}{27^{21}.8^{11}}\)
\(=\frac{\left(3^2\right)^{15}.3^{30}.2^{30}}{\left(3^3\right)^{21}.\left(2^3\right)^{11}}\)
\(=\frac{3^{30}.3^{30}.2^{30}}{3^{63}.2^{33}}\)
\(=\frac{3^{60}.2^{30}}{2^{63}.3^{33}}=\frac{1}{2^3.3^3}=\frac{1}{216}\)
làm mẫu một bài còn lại tương tự nha bn =)
\(\frac{9^{15}.6^{30}}{27^{21}.8^{11}}=\frac{\left(3^2\right)^{15}.\left(2.3\right)^{30}}{\left(3^3\right)^{21}.\left(2^3\right)^{11}}=\frac{3^{60}.2^{30}}{3^{63}.2^{33}}=\frac{1}{3^3.2^3}\)
\(\frac{45^{12}.49^7}{35^{13}.27^8}=\frac{\left(5.3^2\right)^{12}.\left(7^2\right)^7}{\left(5.7\right)^{13}.\left(3^3\right)^8}=\frac{5^{12}.3^{24}.7^{14}}{5^{13}.7^{13}.3^{24}}=\frac{7}{5}\)
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a) \(\frac{2}{3}-4.\left(\frac{1}{2}+\frac{3}{4}\right)\)
= \(\frac{2}{3}-4.\frac{5}{4}\)
= \(\frac{2}{3}-5\)
= \(-\frac{13}{3}\).
b) Câu này là 117 hay \(\frac{11}{7}\) vậy bạn?
Chúc bạn học tốt!
a: \(=\dfrac{7}{2}\left(-\dfrac{3}{4}+\dfrac{5}{13}-\dfrac{9}{4}-\dfrac{8}{13}\right)=\dfrac{7}{2}\cdot\left(-3-\dfrac{3}{13}\right)=\dfrac{7}{2}\cdot\dfrac{-42}{13}=\dfrac{-147}{13}\)
b: \(=-12+\dfrac{8}{9}-\dfrac{5}{18}=\dfrac{-216}{18}+\dfrac{16}{18}-\dfrac{5}{18}=\dfrac{-205}{18}\)
c: \(=\dfrac{45}{4}-\dfrac{19}{7}-\dfrac{21}{4}=6-\dfrac{19}{7}=\dfrac{23}{7}\)
d: \(=\dfrac{-1}{4}\left(\dfrac{152}{11}+\dfrac{68}{11}\right)=\dfrac{-1}{4}\cdot20=-5\)
a) \(=\left(\left(-\frac{1}{4}-\frac{5}{3}\right)+\frac{7}{33}\right)-\left(-\frac{15}{12}+\frac{6}{11}-\frac{48}{49}\right)\)
\(=\left(-\frac{23}{12}+\frac{7}{33}\right)+\frac{15}{12}-\frac{6}{11}+\frac{48}{49}\)
\(=\left(-\frac{23}{12}+\frac{15}{12}\right)+\left(\frac{9}{33}-\frac{6}{11}\right)+\frac{48}{49}\)
\(=-\frac{2}{3}-\frac{3}{11}+\frac{48}{49}\)
\(=\frac{65}{1617}\)
b) \(=\frac{11}{125}+\left(-\frac{17}{18}+\frac{4}{9}\right)+\left(-\frac{5}{7}+\frac{17}{14}\right)\)
\(=\frac{11}{125}-\frac{1}{2}+\frac{1}{2}\)
\(=\frac{11}{125}\)
Sửa đề: \(\frac{49^5+49^7+49^9}{7^{11}+7^{13}+7^{15}+7^{17}+7^{19}+7^{21}}\)
\(=\frac{\left(7^2\right)^5+\left(7^2\right)^7+\left(7^2\right)^9}{7^{11}\left(1+7^2+7^4\right)+7^{17}\left(1+7^2+7^4\right)}\)
\(=\frac{\left(7^{10}+7^{14}+7^{18}\right)}{\left(1+7^2+7^4\right)\left(7^{11}+7^{17}\right)}=\frac{7^{10}\left(1+7^4+7^8\right)}{\left(1+7^2+7^4\right)\cdot7^{11}\left(7^6+1\right)}\)
\(=\frac{1+7^4+7^8}{\left(1+7^2+7^4\right)\cdot7\cdot\left(7^6+1\right)}=\frac{\left(7^8+2\cdot7^4+1\right)-7^4}{\left(7^4+1+7^2\right)\cdot7\cdot\left(7^6+1\right)}\)
\(=\frac{\left(7^4+1\right)^2-7^4}{\left(7^4+7^2+1\right)\cdot7\left(7^6+1\right)}=\frac{\left(7^4+1-7^2\right)\left(7^4+7^2+1\right)}{7\left(7^6+1\right)\left(7^4+7^2+1\right)}\)
\(=\frac{7^4-7^2+1}{7\left(7^6+1\right)}=\frac{7^4-7^2+1}{7\left(7^2+1\right)\left(7^4-7^2+1\right)}=\frac{1}{7\left(7^2+1\right)}=\frac{1}{7\cdot50}=\frac{1}{350}\)