Question

7．对于整数a，b，c，d符号$\left|\begin{array}{l}a\\ d\end{array}\right.{\;}\left.\begin{array}{l}b\\ c\end{array}\right|$表示运算ac-bd，已知$\left|\begin{array}{l}1\\ d\end{array}\right.{\;}\left.\begin{array}{l}b\\ 4\end{array}\right|$=1，则bd的值为-3．

Answer 1

分析 利用定义运算方法，把bd看作一个整体，求得数值即可．

解答 解：∵整数a，b，c，d符号$\left|\begin{array}{l}a\\ d\end{array}\right.{\;}\left.\begin{array}{l}b\\ c\end{array}\right|$表示运算ac-bd，
∴$\left|\begin{array}{l}1\\ d\end{array}\right.{\;}\left.\begin{array}{l}b\\ 4\end{array}\right|$=1×4+bd=1，
解得bd=-3．
故答案为：-3．

点评 此题考查了有理数的混合运算，关键是搞清运算的规定．注意分类思想的应用．