Question

(a–2).(b+1)=5

Answer 1

(a-2)(b+1) = 5

vì a,b ∈ z nên (a-2)(b+1) = 5 

\(\Leftrightarrow\) th1 :  \(\left\{{}\begin{matrix}a-2=-1\\b+1=-5\end{matrix}\right.\) => \(\left\{{}\begin{matrix}a=1\\b=-6\end{matrix}\right.\)

     th2:    \(\left\{{}\begin{matrix}a-2=1\\b+1=5\end{matrix}\right.\)   => \(\left\{{}\begin{matrix}a=3\\b=4\end{matrix}\right.\)

    th3 :    \(\left\{{}\begin{matrix}a-2=-5\\b+1=-1\end{matrix}\right.\) => \(\left\{{}\begin{matrix}a=-3\\b=-2\end{matrix}\right.\)

    th4:     \(\left\{{}\begin{matrix}a-2=5\\b+1=1\end{matrix}\right.\)   => \(\left\{{}\begin{matrix}a=7\\b=0\end{matrix}\right.\)

Kết luận (a;b) = (1; -6); ( 3; 4); (-3; -2); ( 7; 0)