(2xX-1/2)x(2/5+2xX)<0
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`1/2 xx x +3/2 =7`
`=> 1/2 xx x = 7-3/2`
`=> 1/2 xx x = 14/2 -3/2`
`=> 1/2 xx x = 11/2`
`=> x= 11/2 :1/2`
`=> x=11/2 xx2`
`=> x= 22/2`
`=>x=11`
Vậy `x=11`
__
`3/2 xx x -2/7 xx(x-7/2)=18`
`=> 3/2 xx x -2/7x + 1=18`
`=> (3/2 -2/7 )x+ 1 =18`
`=> 17/14 x=18-1`
`=> 17/14x=17`
`=>x=17:17/14`
`=> x=17 xx 14/17`
`=>x=14`
a) \(\dfrac{1}{2}\times x+\dfrac{3}{2}=7\)
\(\dfrac{1}{2}\times x=7-\dfrac{3}{2}\)
\(\dfrac{1}{2}\times x=\dfrac{11}{2}\)
\(x=\dfrac{11}{2}\div\dfrac{1}{2}\\ x=\dfrac{11}{2}\times2\\ x=\dfrac{22}{2}=11\)
b) \(\dfrac{3}{2}\times x-\dfrac{2}{7}\times\left(x-\dfrac{7}{2}\right)=18\)
\(\dfrac{3}{2}\times x-\left(\dfrac{2}{7}x-1\right)=18\)
\(\dfrac{3}{2}\times x-\dfrac{2}{7}x+1=18\)
\(\dfrac{3}{2}x-\dfrac{2}{7}x+1=18\)
\(\dfrac{17}{14}x+1=18\)
\(\dfrac{17}{14}x=18-1\)
\(\dfrac{17}{14}x=17\)
\(x=17\div\dfrac{17}{14}\)
\(x=17\times\dfrac{14}{17}\)
\(x=14\)
\(a)\) \(2x-5=21\)
\(\Leftrightarrow\) \(2x=21+5\)
\(\Leftrightarrow\) \(2x=26\)
\(\Leftrightarrow\) \(x=26:2\)
\(\Leftrightarrow\) \(=13\)
\(b)\) \(\frac{3}{4}+\frac{1}{4}x=\frac{5}{6}\)
\(\Leftrightarrow\) \(\frac{1}{4}x=\frac{5}{6}-\frac{3}{4}\)
\(\Leftrightarrow\) \(\frac{1}{4}x=\frac{1}{12}\)
\(\Leftrightarrow\) \(x=\frac{1}{3}\)
\(\dfrac{5}{4x}-\dfrac{3}{2}=\dfrac{3}{2}+\dfrac{x}{2}\\ \Leftrightarrow5-6x=6x+2x^2\\ \Leftrightarrow2x^2+12x-5=0\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{-6+\sqrt{46}}{2}\\x=\dfrac{-6-\sqrt{46}}{2}\end{matrix}\right.\)
a) \(13\cdot\left(7-x\right)=26\)
\(\Rightarrow7-x=\dfrac{26}{13}\)
\(\Rightarrow7-x=2\)
\(\Rightarrow x=7-2\)
\(\Rightarrow x=5\)
b) \(\left(4x-18\right):3=2\)
\(\Rightarrow4x-18=2\cdot3\)
\(\Rightarrow4x-18=6\)
\(\Rightarrow4x=6+18\)
\(\Rightarrow4x=24\)
\(\Rightarrow x=24:4\)
\(\Rightarrow x=6\)
c) \(2\cdot x+98\cdot2022=98\cdot2023\)
\(\Rightarrow2\cdot x=98\cdot2023-98\cdot2022\)
\(\Rightarrow2\cdot x=98\cdot\left(2023-2022\right)\)
\(\Rightarrow2\cdot x=98\cdot1\)
\(\Rightarrow x=\dfrac{98}{2}\)
\(\Rightarrow x=49\)
d) \(\left(x+1\right)+\left(x+3\right)+\left(x+5\right)+...+\left(x+101\right)=?\)
Thiếu đề
a) \(13.\left(7-x\right)=26\)
\(7-x=26:13\)
\(7-x=2\)
\(x=7-2\)
\(x=5\)
b) \(\left(4x-18\right):3=2\)
\(4x-18=6\)
\(4x=6+18\)
\(4x=24\)
\(x=24:4\)
\(x=6\)
a: =>(x-2)(2x+5)=0
=>x=2 hoặc x=-5/2
c: \(\dfrac{2x}{x-1}-\dfrac{x}{x+1}=1\)
=>\(\dfrac{2x^2+2x-x^2+x}{x^2-1}=1\)
=>x^2+3x=x^2-1
=>3x=-1
=>x=-1/3
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