Đáp án:
Giải thích các bước giải:
a)$Ta có: − 2 x − 11 ⋮ 3 x + 2 $
$⇒ − 3 ( − 2 x − 11 ) ⋮ 3 x + 2$
$⇒ 6 x + 33 ⋮ 3 x + 2⇒ ( 6 x + 4 ) + 29 ⋮ 3 x + 2$
$⇒ 2 ( 3 x + 4 ) + 29 ⋮ 3 x + 2$
$⇒ 29 ⋮ 3 x + 2$
$⇒3 x + 2∈ {±1: ±29}$
\(\left[ \begin{array}{l}3 x + 2=1\\3 x + 2=-1\end{array} \right.\) \(\left[ \begin{array}{l}3 x + 2=29\\3 x + 2=-29\end{array} \right.\)
=>\(\left[ \begin{array}{l}x=- \frac{1}{3}\\x=-1\end{array} \right.\)\(\left[ \begin{array}{l}x=9\\x=-\frac{31}{3} \end{array} \right.\)
$Vì $ $x $ ∈ Z ⇒ $x$ ∈ { $-1,9$ }
