a, Ta có: x + 5 \(⋮\)x + 1
=> ( x + 1 ) + 4 \(⋮\)x + 1
=> 4 \(⋮\)x + 1
=> x + 1 \(\in\)Ư(4) = { -4; -2; -1; 1; 2; 4 }
=> x \(\in\){ -5; -3; -2; 0; 1; 3 }
Vậy:....
b, Ta có: 2x + 5 \(⋮\)x + 1
=> 2.(x+1) + 5 - 2 \(⋮\)x +1
=> 3 \(⋮\)x+1 ( vì: 2(x+1) \(⋮\)x+1)
=> x + 1 \(\in\)Ư(3) = { -3; -1; 1; 3 }
=> x \(\in\){ -4; -2; 0; 2 }
Vậy:......