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TT
2
MC
24 tháng 6 2018
\(2\dfrac{1}{3}-125\%.x=\dfrac{1}{4}\)
⇒ \(\dfrac{7}{3}-\dfrac{125}{100}.x=\dfrac{1}{4}\)
⇒ \(\dfrac{5}{4}x=\dfrac{28}{12}-\dfrac{3}{12}\)
⇒ \(\dfrac{5}{4}x=\dfrac{25}{12}\)
⇒ \(x=\dfrac{25}{12}.\dfrac{4}{5}\)
⇒ \(x=\dfrac{100}{60}\) \(=\dfrac{5}{3}\)
Vậy \(x=\dfrac{5}{3}\).
24 tháng 6 2018
\(2\dfrac{1}{3}\) - 125% . x = \(\dfrac{1}{4}\)
=> \(\dfrac{7}{3}\) - \(\dfrac{125}{100}\) . x = \(\dfrac{1}{4}\)
=> \(\dfrac{5}{4}x\) = \(\dfrac{28}{12}\) - \(\dfrac{3}{12}\)
=> \(\dfrac{5}{4}x\) = \(\dfrac{25}{12}\)
=> \(\dfrac{25}{12}\). \(\dfrac{4}{5}\)
=> \(\dfrac{100}{60}\)\(=\dfrac{5}{3}\)
x = \(\dfrac{5}{3}\)
23 tháng 6 2022
a: 51/56=1-5/56
61/66=1-5/66
mà -5/56<-5/66
nên 51/56<61/66
b: 41/43<1<172/165
c: \(\dfrac{101}{506}>0>-\dfrac{707}{3534}\)
2 tháng 8 2017
a) \(\left(\dfrac{1}{3}-\dfrac{1}{2}\right)^{x-1}=\dfrac{1}{36}\) \(\Leftrightarrow\left(\dfrac{-1}{6}\right)^{x-1}=\dfrac{1}{36}\)
\(\Leftrightarrow\left(\dfrac{-1}{6}\right)^{x-1}=\left(\dfrac{1}{6}\right)^2\)
\(\Leftrightarrow x-1=2\Rightarrow x=3\)
b) \(\dfrac{25}{5^x}=\dfrac{1}{125}\Leftrightarrow\dfrac{25}{5^x}=\dfrac{25}{3125}\Leftrightarrow\dfrac{25}{5^x}=\dfrac{25}{5^5}\Rightarrow x=5\)
2 tháng 8 2017
a) \(\left(\dfrac{1}{3}-\dfrac{1}{2}\right)^{x-1}=\dfrac{1}{36}\Leftrightarrow\left(-\dfrac{1}{6}\right)^{x-1}=\left(-\dfrac{1}{6}\right)^2\)
\(\Leftrightarrow x-1=2\Rightarrow x=2+1=3\)
b) \(\dfrac{25}{5^x}=\dfrac{1}{125}\Leftrightarrow\dfrac{25}{5^x}=\dfrac{25}{3125}\Leftrightarrow\dfrac{25}{5^x}=\dfrac{25}{5^5}\Rightarrow x=5\)
Giờ mới đúng thật nè
12 tháng 3 2017
A = \(\dfrac{17}{15}.\dfrac{-31}{125}.\dfrac{1}{2}.\dfrac{10}{17}.\dfrac{-1}{8}\)
= \(\dfrac{17.\left(-31\right).1.10.\left(-1\right)}{15.125.2.17.8}\)
= \(\dfrac{17.\left[\left(-31\right).\left(-1\right)\right].1.2.5}{5.3.125.17.4.2}\)
= \(\dfrac{31.1}{3.125.4}\)
= \(\dfrac{31}{1500}\)
B = \(\left(\dfrac{11}{4}.\dfrac{-5}{9}-\dfrac{4}{9}.\dfrac{11}{4}\right).\dfrac{8}{33}\)
= \(\left[\dfrac{11}{4}.\left(\dfrac{-5}{9}-\dfrac{4}{9}\right)\right].\dfrac{8}{33}\)
= \(\left(\dfrac{11}{4}.\dfrac{-9}{9}\right).\dfrac{8}{33}\)
= \(\left[\dfrac{11}{4}.\left(-1\right)\right].\dfrac{4.2}{\left(-11\right).\left(-3\right)}\)
= \(\dfrac{-11}{4}.\dfrac{4.2}{\left(-11\right).\left(-3\right)}\)
= \(\dfrac{\left(-11\right).4.2}{4.\left(-11\right)\left(-3\right)}\)
= \(\dfrac{2}{-3}\)
Ok nhá!
2 tháng 4 2017
a) [-125:(50-75)].(-37)
= {-125: (-25)]. (-37)
= 5. (-37)
= - 185
B)
\(\left(2\dfrac{1}{3}+3\dfrac{1}{2}\right):\left(-4\dfrac{1}{6}+3\dfrac{1}{7}\right)+7\dfrac{1}{2}\\ =\left(\dfrac{7}{3}+\dfrac{7}{2}\right):\left(-\dfrac{25}{6}+\dfrac{22}{7}\right)+\dfrac{15}{2}\\ =\dfrac{35}{6}:\dfrac{-43}{42}+\dfrac{15}{2}\\ =-\dfrac{245}{43}+\dfrac{15}{2}\\ =\dfrac{155}{86}=1\dfrac{69}{86}\)
Q
24 tháng 7 2017
3) \(11\dfrac{1}{4}-\left(2\dfrac{5}{7}+5\dfrac{1}{4}\right)\)
\(=\dfrac{45}{4}-\left(7+\dfrac{27}{28}\right)\)
\(=\dfrac{45}{4}-7\dfrac{27}{28}\)
\(=\dfrac{45}{4}-\dfrac{223}{28}\)
\(=\dfrac{23}{7}\)
4) \(\dfrac{11}{125}-\dfrac{17}{18}-\dfrac{5}{7}+\dfrac{4}{9}+\dfrac{17}{14}\)
\(=\dfrac{1386-14875-11250+7000-19125}{15750}\)
\(=-\dfrac{2048}{875}\)
14 tháng 4 2017
1) \(\dfrac{17}{5}\cdot\dfrac{-31}{125}\cdot\dfrac{1}{2}\cdot\dfrac{10}{17}\cdot\dfrac{-1}{2^3}\)
\(=\dfrac{17\cdot\left(-31\right)\cdot1\cdot2\cdot5\cdot\left(-1\right)}{5\cdot125\cdot2\cdot17\cdot8}\)
\(=\dfrac{\left(-31\right)\left(-1\right)}{125\cdot8}\\ =\dfrac{31}{1000}\)
\(=125\left(\dfrac{1}{93}+\dfrac{1}{43}\right)=125\cdot\dfrac{136}{3999}=\dfrac{17000}{3999}\)