Tìm \(x \in {\rm Z}\) trong mỗi trường hợp sau :
\(\eqalign{ & a)5\left( {x + 3} \right) - 3\left( {x - 4} \right) = 39 \cr & b)\left| {2x - 5} \right| + 7 = 10. \cr} \)
\(\eqalign{ & a)\;5\left( {x + 3} \right) - 3\left( {x - 4} \right) = 39 \cr & 5x + 15 - 3x + 12 = 39 \cr & (5x - 3x) + (15 + 12) = 39 \cr & 2x + 27 = 39 \cr & 2x = 39 - 27 \cr & 2x = 12 \Leftrightarrow x = 6 \cr & b)\;\left| {2x - 5} \right| + 7 = 10 \cr & \left| {2x - 5} \right| = 10 - 7 \cr & \left| {2x - 5} \right| = 3 \cr} \)
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\(2x – 5 = 3\) hoặc \(2x – 5 = -3\)
\(2x = 8\) \( 2x = 2\)
\(x = 4\) \(x = 1\)