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LH
19 tháng 3 2020
\(\frac{x}{2}-\left(\frac{3x}{5}-\frac{13}{5}\right)=-\left(\frac{7}{5}+\frac{7}{10x}\right)\) ĐKXĐ: \(x\ne0\)
\(\Leftrightarrow\frac{x}{2}-\frac{3x}{5}+\frac{13}{5}=-\frac{7}{5}-\frac{7}{10x}\)\(\Leftrightarrow\frac{x}{2}-\frac{3x}{5}+\frac{7}{10x}=-\frac{7}{5}-\frac{13}{5}\)
\(\Leftrightarrow\frac{5x^2}{10x}-\frac{6x^2}{10x}+\frac{7}{10x}=-\frac{20}{5}\)\(\Leftrightarrow\frac{5x^2-6x^2+7}{10x}=-\frac{20}{5}\)
\(\Leftrightarrow\frac{-x^2+7}{10x}=-4\)\(\Leftrightarrow x^2-7=40x\)\(\Leftrightarrow x^2-40x-7=0\)
\(\Leftrightarrow x^2-2\cdot x\cdot20+20^2-20^2-7=0\)\(\Leftrightarrow x^2-2\cdot x\cdot20+20^2=400+7\)
\(\Leftrightarrow\left(x-20\right)^2=407\)\(\Leftrightarrow x-20=\pm\sqrt{407}\)\(\Leftrightarrow x\in\left\{20-\sqrt{407};20+\sqrt{407}\right\}\) (TMĐKXĐ)
Vậy \(S=\left\{20-\sqrt{407};20+\sqrt{407}\right\}\)
20 tháng 5 2022
a: 2x-3/2+3/4=-4
=>2x-3/4=-4
=>2x=-13/4
hay x=-13/8
b: \(\left(-\dfrac{2}{3}x-\dfrac{3}{5}\right)\cdot\left(\dfrac{-3}{2}-\dfrac{10}{3}\right)=\dfrac{2}{5}\)
\(\Leftrightarrow-\dfrac{2}{3}x-\dfrac{3}{5}=\dfrac{2}{5}:\dfrac{-29}{6}=\dfrac{-2}{5}\cdot\dfrac{6}{29}=\dfrac{-12}{145}\)
=>2/3x+3/5=12/145
=>2/3x=-15/29
hay x=-45/58
c: \(\dfrac{x}{2}-\left(\dfrac{3}{5}x-\dfrac{13}{5}\right)=-\left(\dfrac{7}{10}x+\dfrac{7}{5}\right)\)
=>1/2x-3/5x+13/5=-7/10x-7/5
=>-1/10x+7/10x=-7/5-13/5
=>3/5x=-2
hay x=-2:3/5=-10/3
15 tháng 7 2021
a) 6x(5x + 3) + 3x(1 – 10x) = 7
⇒ 30x2+18x+3x-30x2=7
⇒21x=7
⇒x=\(\dfrac{7}{21}\)
⇒x= \(\dfrac{1}{3}\)
15 tháng 7 2021
b) (3x – 3)(5 – 21x) + (7x + 4)(9x – 5) = 44
⇒15x-63x2-15+63x + 63x2-35x+36x-20=44
⇒79x-35=44
⇒79x=44+35
⇒79x=79
⇒x=1
TT
0
TT
1
TT
0
LL
1
24 tháng 10 2021
a) \(\dfrac{3x-4}{2x+5}=\dfrac{3x+7}{2x-20}\left(đk:x\ne-\dfrac{5}{2},x\ne10\right)\)
\(\Rightarrow\left(3x-4\right)\left(2x-20\right)=\left(3x+7\right)\left(2x+5\right)\)
\(\Rightarrow6x^2-68x+80=6x^2+29x+35\)
\(\Rightarrow97x=45\Rightarrow x=\dfrac{45}{97}\)
b) \(\dfrac{10x-5}{7x+2}=\dfrac{50x+10}{35x-29}\left(đk:x\ne-\dfrac{2}{7},x\ne\dfrac{29}{35}\right)\)
\(\Rightarrow\left(10x-5\right)\left(35x-29\right)=\left(50x+10\right)\left(7x+2\right)\)
\(\Rightarrow350x^2-465x+145=350x^2+170x+20\)
\(\Rightarrow635x=125\Rightarrow x=\dfrac{25}{127}\)
H
16 tháng 9 2023
\(\dfrac{x}{2}-\left(\dfrac{3x}{5}-\dfrac{13}{5}\right)=\dfrac{7}{5}+\dfrac{7}{10}x\\ \Rightarrow\dfrac{x}{2}-\dfrac{3x}{5}+\dfrac{13}{5}=\dfrac{7}{5}+\dfrac{7x}{10}\\ \Rightarrow\dfrac{5x}{10}-\dfrac{6x}{10}+\dfrac{26}{10}=\dfrac{14}{10}+\dfrac{7x}{10}\\ \Rightarrow\dfrac{5x}{10}-\dfrac{6x}{10}-\dfrac{7x}{10}=\dfrac{14}{10}-\dfrac{26}{10}\\ \Rightarrow\dfrac{-8x}{10}=-\dfrac{12}{10}\\ \Rightarrow\dfrac{-4x}{5}=-\dfrac{6}{5}\\ \Rightarrow-20x=-30\\ \Rightarrow x=\dfrac{3}{2}\)
\(\frac{x}{2}-\left(\frac{3x}{5}-\frac{13}{5}\right)=-\left(\frac{7}{5}+\frac{7}{10x}\right)\)
\(\frac{x}{2}-\frac{3x}{5}+\frac{13}{5}=-\frac{7}{5}-\frac{7}{10x}\)
\(\frac{x}{2}-\frac{x}{15}+\frac{7}{10x}=-\frac{7}{5}-\frac{13}{5}\)
\(\frac{15x}{30}-\frac{2x}{30}+\frac{7}{10x}=-4\)
\(\frac{13x}{30}+\frac{7}{10x}=-4\)
\(13x^2+21=-120x\)
\(13x^2+21+120x=0\)
\(\orbr{\begin{cases}-\frac{60-\sqrt{3327}}{13}\\-\frac{60+\sqrt{3327}}{13}\end{cases}}\)