Toán Lớp 7: Tìm x:
|2-3x|-5=-1
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Toán Lớp 7: Tìm x:
|2-3x|-5=-1
Comments ( 2 )
| 2 – 3x | – 5 = -1
| 2 – 3x | = -1 + 5
| 2 – 3x | = 4
⇒ $\left[\begin{matrix} 2 – 3x = 4 \\ 2 – 3x = -4 \end{matrix}\right.$
$\left[\begin{matrix} 3x = 2 – 4 \\ 3x = 2 – ( -4 )\end{matrix}\right.$
$\left[\begin{matrix} 3x = -2 \\ 3x = 6\end{matrix}\right.$
$\left[\begin{matrix} x = \dfrac{-2}{3} \\ x = 2\end{matrix}\right.$
Vậy x = [ -2 ] / 3 hoặc x = 2
|2 – 3x| – 5 = -1
|2 – 3x| = -1 + 5
|2 – 3x| = 4
=> 2 – 3x in {4; -4}
=> 3x in {-2; 6}
=> x in {-2/3; 2}
Vậy x in {-2/3; 2}