Toán Lớp 7: mk cần gấp ạ
tìm x biết : |x+1|+|3x+2|=5x-1
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Toán Lớp 7: mk cần gấp ạ
tìm x biết : |x+1|+|3x+2|=5x-1
Comments ( 2 )
\left| {x + 1} \right| + \left| {3x + 2} \right| = 5x – 1\\
\to \left[ \begin{array}{l}
x + 1 + 3x + 2 = 5x – 1\left( {DK:x \ge – \dfrac{2}{3}} \right)\\
x + 1 – 3x – 2 = 5x – 1\left( {DK: – \dfrac{2}{3} > x \ge – 1} \right)\\
– x – 1 – 3x – 2 = 5x – 1\left( {DK: – 1 > x} \right)
\end{array} \right.\\
\to \left[ \begin{array}{l}
x = 4\\
7x = 0\\
9x = – 2
\end{array} \right.\\
\to \left[ \begin{array}{l}
x = 4\\
x = 0\left( l \right)\\
x = – \dfrac{2}{9}\left( l \right)
\end{array} \right.\\
\to x = 4
\end{array}\)