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\(a,50\%x-0,2+x=\dfrac{4}{5}\)
\(\Leftrightarrow\dfrac{1}{2}x-0,2+x=\dfrac{4}{5}\)
\(\Leftrightarrow\dfrac{1}{2}x+x=\dfrac{4}{5}+0,2\)
\(\Leftrightarrow\dfrac{3}{2}x=\dfrac{4}{5}+\dfrac{1}{5}\)
\(\Leftrightarrow\dfrac{3}{2}x=1\)
\(\Leftrightarrow x=\dfrac{2}{3}\)
\(b,\left(x-\dfrac{3}{4}\right):\dfrac{1}{2}+\dfrac{3}{2}=\dfrac{25}{2}\)
\(\Leftrightarrow\left(x-\dfrac{3}{4}\right).2=\dfrac{25}{2}-\dfrac{3}{2}\)
\(\Leftrightarrow\left(x-\dfrac{3}{4}\right).2=\dfrac{22}{2}\)
\(\Leftrightarrow x-\dfrac{3}{4}=11:2\)
\(\Leftrightarrow x=\dfrac{11}{2}+\dfrac{3}{4}\)
\(\Leftrightarrow x=\dfrac{25}{4}\)
`a, 1/2 +x=3/4`
`=> x= 3/4 -1/2`
`=> x= 3/4-2/4`
`=>x= 1/4`
`b, 5/2 -x=1/3`
`=> x= 5/2 -1/3`
`=> x= 15/6 - 2/6`
`=>x= 13/6`
`c, 2 . (1/3 +x)=1/5`
`=> 1/3 +x=1/5:2`
`=> 1/3 +x= 1/10`
`=>x= 1/10-1/3`
`=>x= 3/30 - 10/30`
`=>x=-7/30`
`d, 2/3 - (1/2 -x)=1/5`
`=> 1/2-x= 2/3 -1/5`
`=>1/2-x= 10/15 - 3/15`
`=>1/2-x=7/15`
`=>x= 1/2-7/15`
`=>x=1/30`
`1/2 + x = 3/4`
`=> x = 3/4 - 1/2`
`=> x = 1/4`
`5/2 - x = 1/3`
`=> x = 5/2 - 1/3`
`=> x = 13/6`
`2.(1/3 + x) = 1/5`
`=>1/3 + x = 1/10 `
`=> x = 1/10 - 1/3`
`=> x = -7/30`
`2/3 - (1/2 -x)= 1/5`
`=> 1/2 - x = 7/15`
`=> x = 1/2 - 7/15`
`=> x = 1/30`
a) \(\dfrac{1}{2}-\left(x+\dfrac{1}{3}\right)=\dfrac{5}{6}\)
\(\Rightarrow x+\dfrac{1}{3}=\dfrac{1}{2}-\dfrac{5}{6}\)
\(\Rightarrow x+\dfrac{1}{3}=\dfrac{-1}{3}\)
\(\Rightarrow x=\dfrac{-1}{3}-\dfrac{1}{3}\)
\(\Rightarrow x=\dfrac{-2}{3}\)
b)\(\dfrac{3}{4}-\left(x+\dfrac{1}{2}\right)=\dfrac{4}{5}\)
\(\Rightarrow x+\dfrac{1}{2}=\dfrac{3}{4}-\dfrac{4}{5}\)
\(\Rightarrow x+\dfrac{1}{2}=\dfrac{-1}{20}\)
\(\Rightarrow x=\dfrac{-1}{20}-\dfrac{1}{2}\)
\(\Rightarrow x=\dfrac{-11}{20}\)
c) \(\dfrac{3}{35}-\left(\dfrac{3}{5}+x\right)=\dfrac{2}{7}\)
\(\Rightarrow\dfrac{3}{5}+x=\dfrac{3}{35}-\dfrac{2}{7}\)
\(\Rightarrow\dfrac{3}{5}+x=\dfrac{-1}{5}\)
\(\Rightarrow x=\dfrac{-1}{5}-\dfrac{3}{5}\)
\(\Rightarrow x=\dfrac{-4}{5}\)
d)\(\dfrac{2}{3}.x=\dfrac{4}{27}\)
\(\Rightarrow x=\dfrac{4}{27}:\dfrac{2}{3}\)
\(\Rightarrow x=\dfrac{2}{9}\)
e) \(\dfrac{-3}{5}.x=\dfrac{21}{10}\)
\(\Rightarrow x=\dfrac{21}{10}:\dfrac{-3}{5}\)
\(\Rightarrow x=\dfrac{-7}{2}\)
b: \(\dfrac{5}{7}-\dfrac{2}{3}\cdot x=\dfrac{4}{5}\)
=>\(\dfrac{2}{3}x=\dfrac{5}{7}-\dfrac{4}{5}=\dfrac{25-28}{35}=\dfrac{-3}{35}\)
=>\(x=-\dfrac{3}{35}:\dfrac{2}{3}=\dfrac{-3}{35}\cdot\dfrac{3}{2}=-\dfrac{9}{70}\)
c: \(\dfrac{1}{2}x+\dfrac{3}{5}x=-\dfrac{2}{3}\)
=>\(x\left(\dfrac{1}{2}+\dfrac{3}{5}\right)=-\dfrac{2}{3}\)
=>\(x\cdot\dfrac{5+6}{10}=\dfrac{-2}{3}\)
=>\(x\cdot\dfrac{11}{10}=-\dfrac{2}{3}\)
=>\(x=-\dfrac{2}{3}:\dfrac{11}{10}=-\dfrac{2}{3}\cdot\dfrac{10}{11}=\dfrac{-20}{33}\)
d: \(\dfrac{4}{7}\cdot x-x=-\dfrac{9}{14}\)
=>\(\dfrac{-3}{7}\cdot x=\dfrac{-9}{14}\)
=>\(\dfrac{3}{7}\cdot x=\dfrac{9}{14}\)
=>\(x=\dfrac{9}{14}:\dfrac{3}{7}=\dfrac{9}{14}\cdot\dfrac{7}{3}=\dfrac{3}{2}\)
1) \(2x\cdot\left(x-3\right)-5=3x\left(2x-5\right)-4x^2+40\)
\(\Leftrightarrow2x^2-6x-5=6x^2-15x-4x^2+40\)
\(\Leftrightarrow2x^2-6x-5=2x^2-15x+40\)
\(\Leftrightarrow2x^2-6x-5-2x^2+15x-40=0\)
\(\Leftrightarrow9x-45=0\)
<=> x=5
2) x(2x-1)-5(-7)2=2x2-2x+5
<=> 2x2-x-5.49=2x2-2x+5
<=> 2x2-x-245-2x2+2x-5=0
<=> x-250=0
<=> x=250
3) |a-2|=10
\(\Leftrightarrow\orbr{\begin{cases}x-2=10\\x-2=-10\end{cases}\Leftrightarrow\orbr{\begin{cases}x=12\\x=-8\end{cases}}}\)
4) |x|=-5
=> Không tồn tại giá trị của x thỏa mãn vì |x| >=0 với mọi x thuộc Z
a) \(\dfrac{13}{20}+\dfrac{3}{5}+x=\dfrac{5}{6}\)
\(\Rightarrow\dfrac{5}{4}+x=\dfrac{5}{6}\)
\(\Rightarrow x=\dfrac{5}{6}-\dfrac{5}{4}\)
\(\Rightarrow x=\dfrac{-5}{12}\)
b) \(x+\dfrac{1}{3}=\dfrac{2}{5}-\dfrac{-1}{3}\)
\(\Rightarrow x+\dfrac{1}{3}=\dfrac{11}{15}\)
\(\Rightarrow x=\dfrac{11}{15}-\dfrac{1}{3}\)
\(\Rightarrow x=\dfrac{2}{5}\)
c)\(\dfrac{-5}{8}-x=\dfrac{-3}{20}-\dfrac{-1}{6}\)
\(\dfrac{-5}{8}-x=\dfrac{1}{60}\)
\(\Rightarrow x=\dfrac{-5}{8}-\dfrac{1}{60}\)
\(\Rightarrow x=\dfrac{-77}{120}\)
d) \(\dfrac{3}{5}-x=\dfrac{1}{4}+\dfrac{7}{10}\)
\(\Rightarrow\dfrac{3}{5}-x=\dfrac{19}{20}\)
\(\Rightarrow x=\dfrac{3}{5}-\dfrac{19}{20}\)
\(\Rightarrow x=\dfrac{-7}{20}\)
e) \(\dfrac{-3}{7}-x=\dfrac{4}{5}+\dfrac{-2}{3}\)
\(\Rightarrow\dfrac{-3}{7}-x=\dfrac{2}{15}\)
\(\Rightarrow x=\dfrac{-3}{7}-\dfrac{2}{15}\)
\(\Rightarrow x=\dfrac{-59}{105}\)
g) \(\dfrac{-5}{6}-x=\dfrac{7}{12}+\dfrac{-1}{3}\)
\(\Rightarrow\dfrac{-5}{6}-x=\dfrac{1}{4}\)
\(\Rightarrow x=\dfrac{-5}{6}-\dfrac{1}{4}\)
\(\Rightarrow x=\dfrac{-13}{12}\)
1. \(\frac{x-3}{x+2}=\frac{3}{4}\)
=> \(4(x-3)=3(x+2)\)
=> 4x - 12 = 3x + 6
=> 4x - 12 - 3x = 6
=> 4x - 3x - 12 = 6
=> x = 18
2. \(\frac{4-x}{x-1}=\frac{-5}{6}\)
=> 6[4 - x] = -5[x - 1]
=> 24 - 6x = 5 - 5x
=> 24 - 6x - 5 = 5x
=> 24 - 5 = 6x - 5x
=> 19 = x
=> x = 19
3. \(\frac{3-x}{-x+2}=\frac{-1}{3}\)
=> 3[3 - x] = -1[-x + 2]
=> 9 - 3x = x - 2
=> 9 - 3x + x = -2
=> 9 - 4x = -2
=> 4x = 9 - [ -2]
=> 4x = 9 + 2 = 11
=> x = 11/4
4. \(\frac{x-1}{12}=\frac{-3}{1-x}\)
=> [x-1][1-x] = -36
=> -[x-1]2 = -36
=> [x-1]2 = 36
=> [x-1]2 = 62
=> x -1 = 6 hoặc x - 1 = -6
=> x = 7 hoặc x = -5
5 . |x - 3 | - 8 = -4
=> |x - 3| = -4 + 8
=> |x - 3| = 4
=> x - 3 = 4 hoặc x - 3 = -4
=> x = 7 hoặc x = -1
Mấy bài sau tương tự
a) \(\dfrac{x}{5}=\dfrac{2}{5}\)
\(\Rightarrow5x=10\)
\(\Leftrightarrow x=2\)
Vậy x = 2
b) ĐKXĐ: \(x\ne0\)
\(\dfrac{3}{-8}=\dfrac{6}{-x}\)
\(\Rightarrow-3x=-48\)
\(\Leftrightarrow x=16\)
Vậy x = 16
c) \(\dfrac{1}{9}=\dfrac{-2x}{10}\)
\(\Rightarrow-18x=10\)
\(\Leftrightarrow x=-\dfrac{5}{9}\)
Vậy \(x=-\dfrac{5}{9}\)
d) ĐKXĐ: \(x\ne0\)
\(\dfrac{3}{x}-5=\dfrac{-9}{x}+2\)
\(\Leftrightarrow\dfrac{3-5x}{x}=\dfrac{-9+2x}{x}\)
\(\Rightarrow3-5x=-9+2x\)
\(\Leftrightarrow7x=12\)
\(\Leftrightarrow x=\dfrac{12}{7}\)
Vậy \(x=\dfrac{12}{7}\)
e) ĐKXĐ: \(x\ne0\)
\(\dfrac{x}{-2}=\dfrac{-8}{x}\)
\(\Rightarrow x^2=16\)
\(\Leftrightarrow x=\pm4\)
Vậy \(x=\pm4\)
a) Ta có: \(\dfrac{x}{5}=\dfrac{2}{5}\)
\(\Leftrightarrow x=\dfrac{2\cdot5}{5}=2\)
Vậy: x=2
b) Ta có: \(\dfrac{3}{-8}=\dfrac{6}{-x}\)
\(\Leftrightarrow-x=\dfrac{6\cdot\left(-8\right)}{3}=-16\)
hay x=16
Vậy: x=16
`c)1/4x+2/5=7/5`
`=>1/4x=7/5-1/5=1`
`=>x=1:1/4=4`
Vậy `x=4`
`a)2x-2/3=-3/4`
`=>2x=-3/4+2/3=-1/12`
`=>x=-1/24`
Vậy `x=-1/24`