a, -8 < x < 8 (x ∈ Z)
Vì x ∈ Z
Nên x ∈ { -7; -6; -5; -4; -3; -2..........2; 3; 4; 5; 6; 7 }
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b, [( 6X - 72 ) : 2 - 84 ] . 28 = 5628
[( 6X - 72 ) : 2 - 84 ] = 5628 : 28
[( 6X - 72 ) : 2 - 84 ] = 201
( 6X - 72 ) : 2 - 84 = 201
( 6X - 72 ) : 2 = 201 + 84
( 6X - 72 ) : 2 = 285
( 6X - 72 ) = 285 x 2
6X - 72 = 570
6X = 570 + 72
6X = 642
X = 642 : 6
X = 107
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