Ta có : \(\hept{\begin{cases}ab+cd,4=158,4\\ab-cd,4=15,6\end{cases}}\) \(\Leftrightarrow\hept{\begin{cases}ab+cd,4=158,4\\ab=15,6+cd,4\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}15,6+cd,4+cd,4=158,4\\ab=15,6+cd,4\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}2\cdot cd,4=142,8\\ab=15,6+cd,4\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}cd,4=71,4\\ab=87\end{cases}}\)
=> a=8 ;b = 7 ;c = 7 ;d = 1
Nhớ cho mk nha