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20 tháng 8 2018

\(\frac{1}{2}x+\frac{3}{5}x=\frac{-33}{25}\)

\(\Rightarrow\left(\frac{1}{2}+\frac{3}{5}\right)x=\frac{-33}{25}\)

\(\Rightarrow\frac{11}{10}x=\frac{-33}{25}\)

\(\Rightarrow x=\frac{-33}{25}\div\frac{11}{10}\)

\(\Rightarrow x=\frac{-6}{5}\)

Vậy \(x=\frac{-6}{5}.\)

\(\frac{1}{2}.x+\frac{3}{5}.x=\frac{-33}{25}\)

\(\Leftrightarrow x.\left(\frac{1}{2}+\frac{3}{5}\right)=\frac{-33}{25}\)

\(\Leftrightarrow x.\left(\frac{5}{10}+\frac{6}{10}\right)=\frac{-33}{25}\)

\(\Leftrightarrow x.\frac{11}{10}=\frac{-33}{25}\)

\(\Leftrightarrow x=\frac{-33}{25}:\frac{11}{10}=\frac{-33}{25}.\frac{10}{11}\)

\(\Leftrightarrow x=\frac{-330}{275}=\frac{-6}{5}\)

13 tháng 8 2020

a) \(2x\left(x-\frac{1}{7}\right)=0\)

\(\left[{}\begin{matrix}2x=0\\x-\frac{1}{7}=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=0\\x=\frac{1}{7}\end{matrix}\right.\)

Vậy \(x=0;x=\frac{1}{7}\)

b) \(\frac{1}{2}x+\frac{3}{5}x=\frac{-33}{25}\\ \left(\frac{1}{2}+\frac{3}{5}\right)x=\frac{-33}{25}\\ \left(\frac{5}{10}+\frac{6}{10}\right)x=\frac{-33}{25}\\ \frac{11}{10}x=\frac{-33}{25}\\ x=\frac{-33}{25}:\frac{11}{10}\\ x=\frac{-33.10}{25.11}\\ x=\frac{-6}{5}\)

Vậy x = \(\frac{-6}{5}\)

c) \(\left(\frac{2}{3}x-\frac{4}{9}\right)\left(\frac{1}{2}+\frac{-3}{7}:x\right)=0\\ \Rightarrow\left[{}\begin{matrix}\frac{2}{3}x-\frac{4}{9}=0\\\frac{1}{2}+\frac{-3}{7}:x=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}\frac{2}{3}x=\frac{4}{9}\\\frac{-3}{7}:x=\frac{-1}{2}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{4}{9}:\frac{2}{3}=\frac{4.3}{9.2}=\frac{2}{3}\\x=\frac{-3}{7}:\frac{-1}{2}=\frac{-3.2}{7.\left(-1\right)}=\frac{6}{7}\end{matrix}\right.\)

13 tháng 8 2020

a) \(2x\left(x-\frac{1}{7}\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}2x=0\\x-\frac{1}{7}=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=0:2=0\\x=0+\frac{1}{7}=\frac{1}{7}\end{matrix}\right.\)

b) \(\frac{1}{2}x+\frac{3}{5}x=-\frac{33}{25}\)

\(\Rightarrow x\left(\frac{1}{2}+\frac{3}{5}\right)=-\frac{33}{25}\)

\(\Rightarrow x\frac{11}{10}=-\frac{33}{25}\)

\(\Rightarrow x=\left(-\frac{33}{25}\right):\frac{11}{10}=-\frac{33}{25}.\frac{10}{11}=-\frac{6}{5}\)

c) \(\left(\frac{2}{3}x-\frac{4}{9}\right)\left(\frac{1}{2}+\frac{-3}{7}:x\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}\frac{2}{3}x-\frac{4}{9}=0\\\frac{1}{2}+\frac{-3}{7}:x=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}\frac{2}{3}x=0+\frac{4}{9}=\frac{4}{9}\\-\frac{3}{7}:x=0-\frac{1}{2}=-\frac{1}{2}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\frac{4}{9}:\frac{2}{3}=\frac{4}{9}.\frac{3}{2}=\frac{2}{3}\\x=\left(-\frac{3}{7}\right):\frac{-1}{2}=\left(-\frac{3}{7}\right).\left(-2\right)=\frac{6}{7}\end{matrix}\right.\)

a)\(0,45-\left|1,3-x\right|=0\)

\(\Leftrightarrow\left|1,3-x\right|=0,45-0\)

\(\Leftrightarrow\hept{\begin{cases}1,3-x=0,45\\1,3-x=-0,45\end{cases}}\)\(\Leftrightarrow\hept{\begin{cases}x=1,3-0,45\\x=1,3+0,45\end{cases}}\)\(\Leftrightarrow\hept{\begin{cases}x=0,85\\x=1,75\end{cases}}\)

Vậy x = 0,85 ; x = 1,75

b) \(\left|3x-5\right|-\frac{1}{7}=\frac{1}{3}\)

\(\Leftrightarrow\left|3x-5\right|=\frac{1}{3}+\frac{1}{7}\)

\(\Leftrightarrow\left|3x-5\right|=\frac{10}{21}\)

\(\Leftrightarrow\hept{\begin{cases}3x-5=\frac{10}{21}\\3x-5=-\frac{10}{21}\end{cases}}\)\(\Leftrightarrow\hept{\begin{cases}3x=\frac{10}{21}+5\\3x=-\frac{10}{21}+5\end{cases}}\)\(\Leftrightarrow\hept{\begin{cases}3x=\frac{115}{21}\\3x=\frac{95}{21}\end{cases}}\)\(\Leftrightarrow\hept{\begin{cases}x=\frac{115}{63}\\x=\frac{95}{63}\end{cases}}\)

Vậy x = .........................

4 tháng 10 2020

\(\left|x-\frac{2}{5}\right|+\frac{1}{2}=\frac{3}{4}\)

=> \(\left|x-\frac{2}{5}\right|=\frac{1}{4}\)

=> \(\orbr{\begin{cases}x-\frac{2}{5}=\frac{1}{4}\\x-\frac{2}{5}=-\frac{1}{4}\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{13}{20}\\x=\frac{3}{20}\end{cases}}\)

b) \(\left|5-3x\right|+\frac{2}{3}=\frac{11}{6}\)

=> \(\left|5-3x\right|=\frac{7}{6}\)

=> \(\orbr{\begin{cases}5-3x=\frac{7}{6}\\5-3x=-\frac{7}{6}\end{cases}}\Rightarrow\orbr{\begin{cases}3x=\frac{23}{6}\\3x=\frac{37}{6}\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{23}{18}\\x=\frac{37}{18}\end{cases}}\)

c) \(\left|x+\frac{3}{4}\right|-\frac{1}{2}=6^2\)

=> \(\left|x+\frac{3}{4}\right|=36,5\)

=> \(\orbr{\begin{cases}x+\frac{3}{4}=36,5\\x+\frac{3}{4}=-36,5\end{cases}}\Rightarrow\orbr{\begin{cases}x=35,75\\x=-37,25\end{cases}}\)

4 tháng 10 2020

a) \(\left|x-\frac{2}{5}\right|+\frac{1}{2}=\frac{3}{4}\Leftrightarrow\left|x-\frac{2}{5}\right|=\frac{1}{4}\)\(\Leftrightarrow\orbr{\begin{cases}x-\frac{2}{5}=\frac{1}{4}\\x-\frac{2}{5}=\frac{-1}{4}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{13}{20}\\x=\frac{3}{20}\end{cases}}}\)

b) \(\left|5-3x\right|+\frac{2}{3}=\frac{11}{6}\Leftrightarrow\left|5-3x\right|=\frac{7}{6}\)\(\Leftrightarrow\orbr{\begin{cases}5-3x=\frac{7}{6}\\5-3x=\frac{-7}{6}\end{cases}\Leftrightarrow\orbr{\begin{cases}3x=\frac{23}{6}\\3x=\frac{37}{6}\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=\frac{23}{18}\\x=\frac{37}{18}\end{cases}}}\)

c) \(\frac{1}{5}-\left|\frac{1}{5}-x\right|=\frac{1}{5}\Leftrightarrow\left|\frac{1}{5}-x\right|=0\Leftrightarrow x=\frac{1}{5}\)

8 tháng 12 2019

\(\frac{1}{2}x+\frac{3}{5}x=\frac{-33}{10}\)\(\Leftrightarrow\left(\frac{1}{2}+\frac{3}{5}\right)x=\frac{-33}{10}\)

\(\Leftrightarrow\frac{11}{10}x=\frac{-33}{10}\)\(\Leftrightarrow x=\frac{-33}{10}:\frac{11}{10}=\frac{-33}{10}.\frac{10}{11}=-3\)

Vậy \(x=-3\)

\(\frac{1}{2}\cdot x+\frac{3}{5}\cdot x=-\frac{33}{10}\)

\(\left(\frac{1}{2}+\frac{3}{5}\right)\cdot x=-\frac{33}{10}\)

\(\left(\frac{5}{10}+\frac{6}{10}\right)\cdot x=-\frac{33}{10}\)

\(\frac{11}{10}\cdot x=-\frac{33}{10}\)

\(x=-\frac{33}{10}:\frac{11}{10}=-\frac{33}{10}\cdot\frac{10}{11}\)

\(x=-\frac{33}{11}=-3\)

1) Tính: 1. (-3)2 . (\(\frac{3}{4}\) - 0,25) - (3\(\frac{1}{2}\) - 1\(\frac{1}{2}\)) 2. \(\frac{13}{25}\) + \(\frac{6}{41}\) - \(\frac{38}{25}\) + \(\frac{35}{41}\) - \(\frac{1}{2}\) 3. \(\frac{1}{2}\).\(\sqrt{64}\) - \(\sqrt{\frac{4}{25}}\) + (-1)2007 4. (-\(\frac{5}{2}\))2 : (-15) - (-0,45 + \(\frac{3}{4}\)) . (-1\(\frac{5}{9}\)) 5. E = \(\frac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}\) \(\frac{5^4.20^4}{25^5.4^5}\) 2) Tìm x: 1. 3,2x + (-1,2)x +2,7 = -4,9 2. (giá trị tuyệt đói...
Đọc tiếp

1) Tính:

1. (-3)2 . (\(\frac{3}{4}\) - 0,25) - (3\(\frac{1}{2}\) - 1\(\frac{1}{2}\))

2. \(\frac{13}{25}\) + \(\frac{6}{41}\) - \(\frac{38}{25}\) + \(\frac{35}{41}\) - \(\frac{1}{2}\)

3. \(\frac{1}{2}\).\(\sqrt{64}\) - \(\sqrt{\frac{4}{25}}\) + (-1)2007

4. (-\(\frac{5}{2}\))2 : (-15) - (-0,45 + \(\frac{3}{4}\)) . (-1\(\frac{5}{9}\))

5. E = \(\frac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}\)

\(\frac{5^4.20^4}{25^5.4^5}\)

2) Tìm x:

1. 3,2x + (-1,2)x +2,7 = -4,9

2. (giá trị tuyệt đói của x) - 2,2 = 1,3

3. (giá trị tuyệt đối của x + \(\frac{3}{4}\)) - \(\frac{1}{3}\) = 0

4. (giá trị tuyệt đối của x - 1,5) + (giá trị tuyệt đối của 2,5 - x) = 0

5. \(\frac{3}{4}\) : \(\frac{41}{99}\) = x : \(\frac{75}{90}\); 0,4 : x = x : 0,9

6. (2x + 3 )2 = 25

7. (\(\frac{2}{3}\)x -1)(\(\frac{3}{4}\)x + \(\frac{1}{2}\)) = 0

8. x : \(\frac{9}{14}\) = \(\frac{7}{3}\) : x

9. (x - \(\frac{1}{2}\))3 = \(\frac{1}{27}\)

10. (-\(\frac{2}{3}\))2 . x = (-\(\frac{2}{3}\))5

11. \(\frac{37-x}{x+13}\) = \(\frac{3}{7}\)

12. \(\frac{x}{-15}\) = \(\frac{-60}{x}\)

13. \(\frac{-2}{x}\) = \(\frac{-x}{\frac{8}{25}}\)

3) Tìm x, y, z biết:

1. \(\frac{x}{15}\) = \(\frac{y}{20}\) = \(\frac{z}{28}\) và 2x + 3y - 2 = 186

2. 2x = 3y; 5x = 7z và 3x - 7y + 5z = 30

3. \(\frac{x^2}{9}\) = \(\frac{y^2}{16}\) và x2 + y2 = 100

7
23 tháng 12 2019

lol

25 tháng 12 2019
3.1.\(\frac{x}{15}\)=\(\frac{y}{20}\)=\(\frac{z}{28}\)=\(\frac{2x}{30}\)=\(\frac{3y}{60}\)=\(\frac{2x+3y-z}{30+60-28}\)=\(\frac{186}{62}\)=3
=> x=3*15=45
y=3*20=60
z=3*28=84