Tìm x : a ) | 3x – 5 | = | x + 2 | b ) 3x – 2x = -7-5 c ) | -2x – 5 | = | 3-x |

$\text{a.|3x-5|=|x+2|}$

⇔\(\left[ \begin{array}{l}3x-5=x+2 \\3x-5=-x-2\end{array} \right.\) 

⇔\(\left[ \begin{array}{l}x=\dfrac{7}{2} \\x=\dfrac{3}{4}\end{array} \right.\) 

$\text{Vậy}$ $x∈ \begin{Bmatrix} \dfrac{7}{2};\dfrac{3}{4} \end{Bmatrix}$

$b.3x-2x=-7-5$

$⇔x=-12$

$\text{Vậy x=-12}$

$c.|-2x-5|=|3-x|$

⇔\(\left[ \begin{array}{l}-2x-5=3-x\\-2x-5=x-3\end{array} \right.\) 

⇔\(\left[ \begin{array}{l}x=8\\x=\dfrac{-2}{3}\end{array} \right.\) 

$\text{ Vậy}$ $x∈ \begin{Bmatrix} 8 ;\dfrac{-2}{3} \end{Bmatrix}$