\(\frac{7}{2}\)|=\(\left(\frac{2}{5}\right)^{2019}\):
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10 tháng 5 2019

|x - \(\frac{7}{2}\)|=\(\left(\frac{2}{5}\right)^{2019}\):\(\left(\frac{2}{5}\right)^{2018}\)

\(\Leftrightarrow\)|x - \(\frac{7}{2}\)|=\(\frac{2}{5}\)

\(\Leftrightarrow\)\(\left[{}\begin{matrix}x-\frac{7}{2}=\frac{2}{5}\\x-\frac{-7}{2}=\frac{2}{5}\end{matrix}\right.\)

\(\Leftrightarrow\)\(\left[{}\begin{matrix}x=\frac{2}{5}+\frac{7}{2}\\x=\frac{-2}{5}+\frac{7}{2}\end{matrix}\right.\)

\(\Leftrightarrow\)\(\left[{}\begin{matrix}x=\frac{39}{10}\\x=\frac{31}{19}\end{matrix}\right.\)

10 tháng 5 2019

Mk viết sai,phải là \(\left[{}\begin{matrix}x=\frac{39}{10}\\x=\frac{31}{10}\end{matrix}\right.\)

18 tháng 4 2019

a)

\(\frac{11x-1}{4}=\frac{10}{4}\)

⇒ 11x - 1 = 10

11x = 10 + 1 = 11

x = 11 : 11 = 1

b)

\(\left[{}\begin{matrix}3x-6=0\\\frac{x}{9}-\frac{1}{3}=0\end{matrix}\right.\)\(\left[{}\begin{matrix}3x=0+6\\\frac{x}{9}=0+\frac{1}{3}\end{matrix}\right.\)\(\left[{}\begin{matrix}3x=6\\\frac{x}{9}=\frac{1}{3}\end{matrix}\right.\)\(\left[{}\begin{matrix}x=6:3\\\frac{x}{9}=\frac{3}{9}\end{matrix}\right.\)\(\left[{}\begin{matrix}x=2\\x=3\end{matrix}\right.\)

Vậy x = 2 hoặc x = 3

c)

\(M=c\left(\frac{5}{7}+\frac{7}{14}-\frac{17}{14}\right)\)

\(M=c\left(\frac{10}{14}+\frac{7}{14}-\frac{17}{14}\right)\)

\(M=\left(\frac{2018}{2019}-\frac{2019}{2020}\right).0\)

M = 0

d)

\(N=\frac{-7}{13}+2-\frac{19}{13}+\frac{2020}{2018}.\frac{2018}{202}\)

\(N=\left(\frac{-7}{13}-\frac{19}{13}\right)+2+10\)

N = \(-2+2+10\)

N = 10

2 tháng 7 2019

Ủa đề là gì vậy em? :v

2 tháng 7 2019

Tìm x nguyên để các biểu thức sau đạt giá trị lớn nhất

17 tháng 8 2016

\(a\left(x-\frac{1}{2}\right)^3=\frac{1}{27}\\ =>\left(x-\frac{1}{2}\right)=\frac{1}{3}\\ =>x=\frac{1}{3}+\frac{1}{2}\\ =>x=\frac{5}{6}\)

b) \(\left(x+\frac{1}{2}\right)^2=\frac{4}{25}\\ =>\left(x+\frac{1}{2}\right)=\frac{2}{5}\\ =>x=\frac{-1}{10}\)

d) (2x+3)2016=(2x+3)2018 khi 2x+3=0 hoặc 1 

Nếu 2x+3=0 

=2x=-3 ( loại ) 

Nếu 2x+3=1

=>2x=-2

=>x=-1 ( thỏa ) 

 

30 tháng 3 2017

cho vài k đi bà con ơi

16 tháng 4 2019

a) \(\frac{2}{5}x-x=\frac{\left(-2018\right)^0}{5^2}\\ x\left(\frac{2}{5}-1\right)=\frac{1}{25}\\ x\left(\frac{2}{5}-\frac{5}{5}\right)=\frac{1}{25}\\ x\cdot\frac{-3}{5}=\frac{1}{25}\\ x=\frac{1}{25}:\frac{-3}{5}\\ x=\frac{1}{25}\cdot\frac{-5}{3}\\ x=\frac{-1}{15}\)Vậy \(x=\frac{-1}{15}\)

b) \(\left|-1\frac{1}{2}x+2x\right|-\frac{7}{4}=0,5\\ \left|x\left(-1\frac{1}{2}+2\right)\right|-\frac{7}{4}=\frac{1}{2}\\ \left|x\cdot\frac{1}{2}\right|=\frac{1}{2}+\frac{7}{4}\\ \left|x\cdot\frac{1}{2}\right|=\frac{2}{4}+\frac{7}{4}\\ \left|x\cdot\frac{1}{2}\right|=\frac{9}{4}\\ \Rightarrow\left[{}\begin{matrix}x\cdot\frac{1}{2}=\frac{9}{4}\\x\cdot\frac{1}{2}=\frac{-9}{4}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{9}{4}:\frac{1}{2}\\x=\frac{-9}{4}:\frac{1}{2}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{9}{4}\cdot2\\x=\frac{-9}{4}\cdot2\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{9}{2}\\x=\frac{-9}{2}\end{matrix}\right.\)Vậy \(x\in\left\{\frac{9}{2};\frac{-9}{2}\right\}\)

c) \(x+\left(x+\frac{2}{7}\right)+\frac{-5}{11}=\frac{4}{11}\\ x+x+\frac{2}{7}=\frac{4}{11}-\frac{-5}{11}\\ 2x+\frac{2}{7}=\frac{4}{11}+\frac{5}{11}\\ 2x+\frac{2}{7}=\frac{9}{11}\\ 2x=\frac{9}{11}-\frac{2}{7}\\ 2x=\frac{63}{77}-\frac{22}{77}\\ 2x=\frac{41}{77}\\ x=\frac{41}{77}:2\\ x=\frac{41}{77\cdot2}\\ x=\frac{41}{154}\)Vậy \(x=\frac{41}{154}\)

d) \(\left|0,25x-20\%\right|+\frac{3}{8}=1\frac{3}{8}\\ \left|\frac{1}{4}x-\frac{1}{5}\right|=1\frac{3}{8}-\frac{3}{8}\\ \left|\frac{1}{4}x-\frac{1}{5}\right|=1\\ \Rightarrow\left[{}\begin{matrix}\frac{1}{4}x-\frac{1}{5}=1\\\frac{1}{4}x-\frac{1}{5}=-1\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}\frac{1}{4}x=1+\frac{1}{5}\\\frac{1}{4}x=\left(-1\right)+\frac{1}{5}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}\frac{1}{4}x=\frac{5}{5}+\frac{1}{5}\\\frac{1}{4}x=\frac{-5}{5}+\frac{1}{5}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}\frac{1}{4}x=\frac{6}{5}\\\frac{1}{4}x=\frac{-4}{5}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{6}{5}:\frac{1}{4}\\x=\frac{-4}{5}:\frac{1}{4}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{6}{5}\cdot4\\x=\frac{-4}{5}\cdot4\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{24}{5}\\x=\frac{-16}{5}\end{matrix}\right.\)Vậy \(x\in\left\{\frac{24}{5};\frac{-16}{5}\right\}\)