x + 11 \(\in\)Ư(1001) = {-1001; -143; -91; -77; -13; -11; -7; -1; 1; 7; 11; 13; 77; 91; 143; 1001}
+) x + 11 = -1001 => x = -1001-11=-1012
+) x + 11 = -143 => x = -143-11=-154
Tương tự
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Vậy x \(\in\){-1012; -154; -102; -88; -24; -22; -18; -12; -10; -4; 0; 2; 66; 80; 132; 990}.