Question

(2x+11) chia hết (x-1)

 

Answer 1

\(2x+11⋮x-1\)

=>\(2x-2+13⋮x-1\)

=>\(13⋮x-1\)

=>\(x-1\in\left\{1;-1;13;-13\right\}\)

=>\(x\in\left\{2;0;14;-12\right\}\)

Answer 2

Ta có : 2x + 11 ⋮ x - 1

=> 2x - 2 + 13 ⋮ x - 1

=> (2x - 2) + 13 ⋮ x - 1

=> 2(x - 1) + 13 ⋮ x - 1

Vì 2( x - 1) ⋮ x - 1 nên 13 ⋮ x - 1

=> x - 1 ∈ Ư(13) ∈ {-13;-1;1;13}

=>  x ∈ {-12;0;2;14}