a>16-x/4=2x+1/3

<=>3[16-x)=4(2x+1)

<=>48-3x=8x+8

<=>-3x-8x=8-48

<=>-5x=-40

<=>x=8

a) \(\dfrac{x+5}{3\left(x-1\right)}+1=\dfrac{3x+7}{5\left(x-1\right)}\) ( đk: \(x\ne1\))

\(\Leftrightarrow\dfrac{5\left(x+5\right)}{15\left(x-1\right)}+\dfrac{15\left(x-1\right)}{15\left(x-1\right)}=\dfrac{3\left(3x+7\right)}{15\left(x-1\right)}\)

\(\Rightarrow5\left(x+5\right)+15\left(x-1\right)=3\left(3x+7\right)\)

\(\Leftrightarrow5x+25+15x-15=9x+21\)

\(\Leftrightarrow5x+15x-9x=21-25+15\)

\(\Leftrightarrow11x=11\Leftrightarrow x=1\) (loại)

Vậy tập nghiệm: \(S=\varnothing\)

b) \(\dfrac{3x-1}{x-1}-\dfrac{2x+5}{x+3}-\dfrac{8}{x^2+2x-3}=1\)  (đk: \(x\ne1,x\ne-3\))

\(\Leftrightarrow\dfrac{\left(3x-1\right)\left(x+3\right)}{x^2+2x-3}-\dfrac{\left(2x+5\right)\left(x-1\right)}{x^2+2x-3}-\dfrac{8}{x^2+2x-3}=\dfrac{x^2+2x-3}{x^2+2x-3}\)

\(\Rightarrow\left(3x-1\right)\left(x+3\right)-\left(2x+5\right)\left(x-1\right)-8=x^2+2x-3\)

\(\Leftrightarrow3x^2+9x-x-3-2x^2+2x-5x+5-8=x^2+2x-3\)

\(\Leftrightarrow3x=3\Leftrightarrow x=1\) (loại)

Vậy tập nghiệm: \(S=\varnothing\)

e) ĐK : \(\left\{{}\begin{matrix}1+3x\ne0\\1-3x\ne0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}3x\ne-1\\3x\ne1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ne\dfrac{-1}{3}\\x\ne\dfrac{1}{3}\end{matrix}\right.\)

\(\Leftrightarrow\dfrac{12}{\left(1-3x\right)\left(1+3x\right)}=\dfrac{\left(1-3x\right)^2-\left(1+3x\right)^2}{\left(1+3x\right)\left(1-3x\right)}\)

\(\Leftrightarrow12\left(1+3x\right)\left(1-3x\right)=\left(1-3x\right)\left(1+3x\right)\left(1-3x-1-3x\right)\left(1-3x+1+3x\right)\)

\(\Leftrightarrow12=\left(-6x\right).2\Leftrightarrow6=-6x\)

\(\Leftrightarrow x=-1\left(TM\right)\)

Câu 1:

\(\left(x-2\right)\left(x^2+2x+4\right)+25x=x\left(x+5\right)\left(x-5\right)+8\)

\(\Leftrightarrow x^3-8+25x=x\left(x^2-25\right)+8\)

\(\Leftrightarrow x^3-8+25x=x^3-25x+8\)

\(\Leftrightarrow x^3-8+25x-x^3+25x-8=0\)

\(\Leftrightarrow50x-16=0\)

\(\Leftrightarrow50x=16\)

\(\Leftrightarrow x=\dfrac{8}{25}\)

Câu 2 :

\(\dfrac{x+5}{4}+\dfrac{3+2x}{3}=\dfrac{6x-1}{3}-\dfrac{1-2x}{12}\)

<=> \(\dfrac{3\left(x+5\right)}{12}+\dfrac{4\left(3+2x\right)}{12}=\dfrac{4\left(6x-1\right)}{12}-\dfrac{1-2x}{12}\)

<=>\(\dfrac{3x+15+12+8x}{12}=\dfrac{24x-4-1+2x}{12}\)

<=> 3x + 15 + 12 + 8x = 24x - 4 - 1 +2x

<=> 11x+27 = 26x -5

<=> ( 26x - 5 ) - ( 11x + 27 ) = 0

<=> 15x - 32 = 0

<=> 15x = 32

<=> x = \(\dfrac{32}{15}\)

Câu 3:

x - 4/3 - 3x - 1/12 = 3x + 1/4 + 9x - 2/8

<=> 4x - 16 - 3x + 1/12 = 6x + 2 + 9x - 2/8

<=> x - 15/12 = 15x/8

<=> 8x - 120 = 180x

<=> 120 = -172x <=> x = -172/120 = -43/30

a: \(\Leftrightarrow\dfrac{x\left(x+2\right)}{x\left(x-2\right)}-\dfrac{2}{x\left(x-2\right)}=\dfrac{x-2}{x\left(x-2\right)}\)

Suy ra: \(x^2+2x-2=x-2\)

\(\Leftrightarrow x^2+x=0\)

=>x(x+1)=0

=>x=0(loại) hoặc x=-1(nhận)

b: \(\Leftrightarrow x^2+x+1-3x^2=2x\left(x-1\right)\)

\(\Leftrightarrow-2x^2+x+1-2x^2+2x=0\)

\(\Leftrightarrow-4x^2+3x+1=0\)

\(\Leftrightarrow4x^2-3x-1=0\)

\(\Leftrightarrow4x^2-4x+x-1=0\)

\(\Leftrightarrow\left(x-1\right)\left(4x+1\right)=0\)

=>x=1(loại) hoặc x=-1/4(nhận)

a: \(=\dfrac{2x-2x+y}{2\left(2x-y\right)}=\dfrac{y}{2\left(2x-y\right)}\)

b: \(=\dfrac{3x+1}{\left(x-1\right)\left(x+1\right)}-\dfrac{x}{2\left(x-1\right)}\)

\(=\dfrac{6x+2-x^2-x}{2\left(x-1\right)\left(x+1\right)}\)

\(=\dfrac{-x^2+5x+2}{2\left(x-1\right)\left(x+1\right)}\)

c: \(=\dfrac{1}{x+2}+\dfrac{x+8}{3x\left(x+2\right)}\)

\(=\dfrac{3x+x+8}{3x\left(x+2\right)}=\dfrac{4x+8}{3x\left(x+2\right)}=\dfrac{4}{3x}\)

d: \(=\dfrac{4x+6-2x^2+3x+2x+1}{\left(2x-3\right)\left(2x+3\right)}\)

\(=\dfrac{-2x^2+9x+7}{\left(2x-3\right)\left(2x+3\right)}\)

a, \(\left|3x+1\right|>2\)

\(\Leftrightarrow\left(\left|3x+1\right|\right)^2>4\)

\(\Leftrightarrow9x^2+6x+1>4\)

\(\Leftrightarrow9x^2+6x-3>0\)

\(\Leftrightarrow3\left(3x-1\right)\left(x+1\right)>0\)

\(\Leftrightarrow\left[{}\begin{matrix}x>\dfrac{1}{3}\\x< -1\end{matrix}\right.\)

b, \(\left|2x-1\right|\le1\)

\(\Leftrightarrow\left(\left|2x-1\right|\right)^2\le1\)

\(\Leftrightarrow4x^2-4x+1\le1\)

\(\Leftrightarrow4x\left(x-1\right)\le0\)

\(\Leftrightarrow0\le x\le1\)

c, ĐK: \(x\ne13\)

\(\left|\dfrac{2}{x-13}\right|>\dfrac{8}{9}\)

\(\Leftrightarrow\dfrac{1}{\left|x-13\right|}>\dfrac{4}{9}\)

\(\Leftrightarrow4\left|x-13\right|< 9\)

\(\Leftrightarrow16\left(x^2-26x+169\right)< 81\)

\(\Leftrightarrow16x^2-416x+2623< 0\)

\(\Leftrightarrow\dfrac{43}{4}< x< \dfrac{61}{4}\)

\(\Rightarrow\) Có hai giả trị thỏa mãn yêu cầu bài toán