\(3x\dfrac{7}{10}+\dfrac{7}{10}x5+2x\dfrac{7}{10}\)
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a)Ta có: \(\dfrac{x}{2}-\left(\dfrac{3x}{5}-\dfrac{13}{5}\right)=-\left(\dfrac{7}{5}+\dfrac{7}{10}x\right)\)
\(\Leftrightarrow\dfrac{x}{2}-\dfrac{3x-13}{5}=\dfrac{-7}{5}-\dfrac{7x}{10}\)
\(\Leftrightarrow\dfrac{5x}{10}-\dfrac{2\left(3x-13\right)}{10}=\dfrac{-14}{10}-\dfrac{7x}{10}\)
\(\Leftrightarrow5x-6x+26=-14-7x\)
\(\Leftrightarrow-x+26+14+7x=0\)
\(\Leftrightarrow6x=-40\)
hay \(x=-\dfrac{20}{3}\)
d) Ta có: \(\dfrac{2x-3}{2}+\dfrac{-3}{2}=\dfrac{5-3x}{6}-\dfrac{1}{3}\)
\(\Leftrightarrow\dfrac{3\left(2x-3\right)}{6}+\dfrac{-9}{6}=\dfrac{5-3x}{6}-\dfrac{2}{6}\)
\(\Leftrightarrow6x-9-9=5-3x-2\)
\(\Leftrightarrow6x-18-3+3x=0\)
\(\Leftrightarrow x=\dfrac{7}{3}\)
\(b,\Rightarrow\dfrac{x}{2}-\dfrac{3x}{5}-\dfrac{13}{5}=-\dfrac{7}{5}-\dfrac{7x}{10}\\ \Rightarrow\dfrac{1}{2}x-\dfrac{3}{5}x+\dfrac{7}{10}x=\dfrac{6}{5}\\ \Rightarrow\dfrac{3}{5}x=\dfrac{6}{5}\Rightarrow x=2\\ c,\Rightarrow\dfrac{2x-3}{3}-\dfrac{5-3x}{6}=-\dfrac{1}{3}+\dfrac{3}{2}=\dfrac{7}{6}\\ \Rightarrow\dfrac{4x-6-5+3x}{6}=\dfrac{7}{6}\\ \Rightarrow7x-11=7\Rightarrow x=\dfrac{18}{7}\\ d,\Rightarrow\dfrac{2}{3x}+\dfrac{7}{x}=\dfrac{4}{5}+2+\dfrac{3}{12}=\dfrac{61}{20}\\ \Rightarrow\dfrac{23}{3x}=\dfrac{61}{20}\\ \Rightarrow183x=460\\ \Rightarrow x=\dfrac{460}{183}\\ e,\Rightarrow2\left(x-1\right)-\left(x-1\right)^2=0\\ \Rightarrow\left(x-1\right)\left(2-x+1\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=1\\x=3\end{matrix}\right.\)
e: Ta có: \(\left(x-1\right)^2=2\left(x-1\right)\)
\(\Leftrightarrow\left(x-1\right)\left(x-3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=3\end{matrix}\right.\)
1.
<=> \(\left[{}\begin{matrix}4-3x=0\\10-5x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{4}{3}\\x=2\end{matrix}\right.\)
2.
<=>\(\left[{}\begin{matrix}7-2x=0\\4+8x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{2}\\x=-\dfrac{1}{2}\end{matrix}\right.\)
3.
<=>\(\left[{}\begin{matrix}9-7x=0\\11-3x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{9}{7}\\x=\dfrac{11}{3}\end{matrix}\right.\)
4.
<=>\(\left[{}\begin{matrix}7-14x=0\\x-2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=2\end{matrix}\right.\)
5.
<=>\(\left[{}\begin{matrix}\dfrac{7}{8}-2x=0\\3x+\dfrac{1}{3}=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{16}\\x=-\dfrac{1}{9}\end{matrix}\right.\)
6,7. ko đủ điều kiện tìm
a: \(\frac{2x+2}{5}+\frac{3}{10}<\frac{3x-2}{4}\)
=>\(\frac{4\left(2x+2\right)}{20}+\frac{6}{20}<\frac{5\left(3x-2\right)}{20}\)
=>4(2x+2)+6<5(3x-2)
=>8x+8+6<15x-10
=>8x+14<15x-10
=>-7x<-24
=>\(x>\frac{24}{7}\)
b: \(\frac{2+x}{3}<\frac{3+2x}{5}\)
=>\(\frac{x+2}{3}-\frac{2x+3}{5}<0\)
=>\(\frac{5\left(x+2\right)-3\left(2x+3\right)}{15}<0\)
=>5(x+2)-3(2x+3)<0
=>5x+10-6x-9<0
=>-x+1<0
=>-x<-1
=>x>1
d: \(1+\frac{3\left(x+1\right)}{10}>\frac{x-2}{5}\)
=>\(\frac{10+3\left(x+1\right)}{10}>\frac{2\left(x-2\right)}{10}\)
=>3(x+1)+10>2(x-2)
=>3x+3+10>2x-4
=>3x+13>2x-4
=>3x-2x>-4-13
=>x>-17
e: \(\frac{2x-7}{6}\ge\frac{3x-7}{2}\)
=>\(\frac{2x-7}{6}\ge\frac{3\left(3x-7\right)}{6}\)
=>2x-7>=3(3x-7)
=>2x-7>=9x-21
=>-7x>=-14
=>x<=2
f: \(\frac{2x-1}{3}>\frac{3x+1}{2}\)
=>\(\frac{2x-1}{3}-\frac{3x+1}{2}>0\)
=>\(\frac{2\left(2x-1\right)-3\left(3x+1\right)}{6}>0\)
=>2(2x-1)-3(3x+1)>0
=>4x-2-9x-3>0
=>-5x-5>0
=>5x+5<0
=>5x<-5
=>x<-1
Hai câu là hoàn toàn giống nhau, mình làm câu a, câu b bạn tự làm tương tự:
ĐKXĐ: ...
Nhận thấy \(x=0\) ko phải nghiệm, pt tương đương:
\(\frac{4}{4x+\frac{7}{x}-8}+\frac{3}{4x+\frac{7}{x}-10}=1\)
Đặt \(4x+\frac{7}{x}-10=t\)
\(\Leftrightarrow\frac{4}{t+2}+\frac{3}{t}=1\Leftrightarrow4t+3\left(t+2\right)=t\left(t+2\right)\)
\(\Leftrightarrow t^2-5t-6=0\Rightarrow\left[{}\begin{matrix}t=-1\\t=6\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}4x+\frac{7}{x}-10=-1\\4x+\frac{7}{x}-10=6\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}4x^2-9x+7=0\\4x^2-16x+7=0\end{matrix}\right.\) (bấm casio)
\(a,=\dfrac{\left(x-5\right)\left(x+5\right)\left(3x-7\right)}{2\left(x+5\right)}=\dfrac{\left(x-5\right)\left(3x-7\right)}{2}\\ b,=\dfrac{\left(x-2\right)\left(x+2\right)}{x\left(x-1\right)}\cdot\dfrac{x-1}{x\left(x+2\right)}=\dfrac{x-2}{x^2}\)
a) \(\left(x^2-25\right):\dfrac{2x+10}{3x-7}=\left(x-5\right)\left(x+5\right).\dfrac{3x-7}{2\left(x+5\right)}=\dfrac{\left(x-5\right)\left(3x-7\right)}{2}\)
b) \(\dfrac{x^2-4}{x^2-x}:\dfrac{x^2+2x}{x-1}=\dfrac{\left(x-2\right)\left(x+2\right)}{x\left(x-2\right)}.\dfrac{x-1}{x\left(x+2\right)}=\dfrac{x-1}{x^2}\)
a) ĐKXĐ: \(10-5x< 0\Leftrightarrow5x>10\Leftrightarrow x>2\)
b) ĐKXĐ: \(7-3x>0\Leftrightarrow3x< 7\Leftrightarrow x< \dfrac{7}{3}\)
c) ĐKXĐ: \(-5-2x\ge0\Leftrightarrow2x\le-5\Leftrightarrow x\le-\dfrac{5}{2}\)
`x/2-(3x/5-13/5)=7/5-7/10x`
`=>x/2-3x/5+13/5=7/5+(7x)/10`
`=>(5x)/10-(6x)/10-(7x)/10=7/5-13/5`
`=>(5x-6x-7x)/10=(7-13)/5`
`=>(-4x)/5=-6/5`
`=>4x=6`
`=>x=3/2`
`=7/10xx(3+5+2)`
`=7/10xx10=7`