Đáp án:
Giải thích các bước giải:
\(\begin{array}{l}\left\{ \begin{array}{l}a - b = 5\\a.b = - 6\end{array} \right. \Rightarrow \left\{ \begin{array}{l}a = b + 5\\\left( {b + 5} \right).b = - 6\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}a = b + 5\\{b^2} + 5b + 6 = 0\end{array} \right.\\ \Leftrightarrow \left\{ \begin{array}{l}a = b + 5\\\left( {b + 2} \right)\left( {b + 3} \right) = 0\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}a = b + 5\\\left[ \begin{array}{l}b = - 2\\b = - 3\end{array} \right.\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}b = - 2 \Rightarrow a = 3\\b = - 3 \Rightarrow a = 2\end{array} \right.\end{array}\)
