Câu hỏi của Ngọc

Question

Tìm x : a) $\frac{3x+2}{-4x+5}$=$\frac{-4}{3}$                c) $\frac{\left(2x+1\right)}{5}=\frac{3}{2x-1}$           e)$\frac{\left|6x+1\right|}{4}=\frac{2}{4}$b) \(\frac{2.\left|x\right|+5...

Đỗ Ngọc Hải · Accepted Answer

a) $\frac{3x+2}{-4x+5}=-\frac{4}{3}\left(ĐKXĐ:x\ne\frac{5}{4}\right)$$\Rightarrow3\left(3x+2\right)=-4\left(-4x+5\right)$$\Leftrightarrow9x+6=16x-20$$\Leftrightarrow7x=26$$\Leftrightarrow x=\frac{26}{7}$b) $\frac{2\left|x\right|+5}{-4x+3}=-\frac{5}{4}$(Thôi bài sau tự tìm đkxđ nhá)$\Rightarrow8\left|x\right|+20=20x-15$$\Leftrightarrow8\left|x\right|-20x+35$$\left(1\right)$TH1: Nếu $x\ge0$thì $\left(1\right)\Leftrightarrow8x-20x+35=0\Leftrightarrow x=\frac{35}{12}\left(tm\right)$TH2: Nếu $x< 0$thì $\left(1\right)\Leftrightarrow-8x-20x+35=0\Leftrightarrow x=\frac{35}{28}\left(ktm\right)$Vậy x=35/12c)$\frac{2x+1}{5}=\frac{3}{2x-1}$$\Rightarrow4x^2-1=15$$\Leftrightarrow4x^2=16$$\Leftrightarrow x^2=4$$\Leftrightarrow\orbr{\begin{cases}x=2\x=-2\end{cases}}$d)$\frac{x+1}{2x+1}=\frac{0,5x+2}{x+3}$$\Leftrightarrow\left(x+1\right)\left(x+3\right)=\left(2x+1\right)\left(0,5x+2\right)$$\Leftrightarrow x^2+4x+3=x^2+4,5x+2$$\Leftrightarrow0,5x=1$$\Leftrightarrow x=2$e) $\frac{\left|6x+1\right|}{4}=\frac{2}{4}$$\Leftrightarrow\left|6x+1\right|=2$$\Leftrightarrow\orbr{\begin{cases}6x+1=2\6x+1=-2\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{6}\x=-\frac{1}{2}\end{cases}}}$g)$\frac{\left|3x-5\right|}{3}=\frac{\left|x\right|}{2}$$\Leftrightarrow\frac{\left|3x-5\right|}{\left|x\right|}=\frac{3}{4}$$\Leftrightarrow\left|\frac{3x-5}{x}\right|=\frac{3}{4}$$\Leftrightarrow\orbr{\begin{cases}\frac{3x-5}{x}=\frac{3}{4}\\frac{3x-5}{x}=-\frac{3}{4}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{20}{9}\x=\frac{4}{3}\end{cases}}}$Mỏi tay quá, xin tý  cho sảng khoái nào!!Câu trả lời: a) $\frac{3x+2}{-4x+5}=-\frac{4}{3}\left(ĐKXĐ:x\ne\frac{5}{4}\right)$$\Rightarrow3\left(3x+2\right)=-4\left(-4x+5\right)$$\Leftrightarrow9x+6=16x-20$$\Leftrightarrow7x=26$$\Leftrightarrow x=\frac{26}{7}$b) $\frac{2\left|x\right|+5}{-4x+3}=-\frac{5}{4}$(Thôi bài sau tự tìm đkxđ nhá)$\Rightarrow8\left|x\right|+20=20x-15$$\Leftrightarrow8\left|x\right|-20x+35$$\left(1\right)$TH1: Nếu $x\ge0$thì $\left(1\right)\Leftrightarrow8x-20x+35=0\Leftrightarrow x=\frac{35}{12}\left(tm\right)$TH2: Nếu $x< 0$thì $\left(1\right)\Leftrightarrow-8x-20x+35=0\Leftrightarrow x=\frac{35}{28}\left(ktm\right)$Vậy x=35/12c)$\frac{2x+1}{5}=\frac{3}{2x-1}$$\Rightarrow4x^2-1=15$$\Leftrightarrow4x^2=16$$\Leftrightarrow x^2=4$$\Leftrightarrow\orbr{\begin{cases}x=2\x=-2\end{cases}}$d)$\frac{x+1}{2x+1}=\frac{0,5x+2}{x+3}$$\Leftrightarrow\left(x+1\right)\left(x+3\right)=\left(2x+1\right)\left(0,5x+2\right)$$\Leftrightarrow x^2+4x+3=x^2+4,5x+2$$\Leftrightarrow0,5x=1$$\Leftrightarrow x=2$e) $\frac{\left|6x+1\right|}{4}=\frac{2}{4}$$\Leftrightarrow\left|6x+1\right|=2$$\Leftrightarrow\orbr{\begin{cases}6x+1=2\6x+1=-2\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{6}\x=-\frac{1}{2}\end{cases}}}$g)$\frac{\left|3x-5\right|}{3}=\frac{\left|x\right|}{2}$$\Leftrightarrow\frac{\left|3x-5\right|}{\left|x\right|}=\frac{3}{4}$$\Leftrightarrow\left|\frac{3x-5}{x}\right|=\frac{3}{4}$$\Leftrightarrow\orbr{\begin{cases}\frac{3x-5}{x}=\frac{3}{4}\\frac{3x-5}{x}=-\frac{3}{4}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{20}{9}\x=\frac{4}{3}\end{cases}}}$Mỏi tay quá, xin tý  cho sảng khoái nào!!

Ngọc · Answer

Hôm nay tặng bn 3 k , ngày mai mk tặng tiếp 3 k nx nhé ^^ Thanks bn nhiều lắm !Câu trả lời: Hôm nay tặng bn 3 k , ngày mai mk tặng tiếp 3 k nx nhé ^^ Thanks bn nhiều lắm !

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