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Tìm số nguyên x trong mỗi trường hợp sau:
\(\eqalign{ & a) \;- 22 – \left( { – x + 5} \right) = 13 \cr & b)\;45 – 25 = – x + 21 \cr & c)\;\left| {x + 1} \right| = 5 \cr & d)\;\left| x \right| – \left( { – 4} \right) = 17 – 3. \cr} \)
a) \(-22 – (-x +5) = 13 \)
\(-(-x + 5) = 13 + 22\)
\(x -5 = 35\)
\(x = 35 + 5\)
\(x = 40\)
b) \(45 – 25 = -x + 21\)
\(20 = -x + 21\)
Advertisements (Quảng cáo)
\( x = 21 – 20\)
\(x = 1\)
c) \(\left| {x + 1} \right| = 5\)
\(x + 1 = 5\) hoặc \(x + 1 = -5\)
\(x = 5 – 1\) \( x = -5 – 1\)
\(x = 4\) \( x = -6\)
\(\eqalign{ & d)\;\left| x \right| – ( – 4) = 17 – 3 \cr & \left| x \right| + 4 = 14 \cr & \left| x \right| = 14 – 4 = 10 \cr} \)
\(\Rightarrow x = 10\) hoặc \(x = -10\)