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Section   9.12   Negating Logical Expressions 
 
 Sometimes you might want to check whether a certain logical expression is NOT true, rather than finding out whether it is true. There are several ways to do so.
Video Description. 
!(A && B) == !A || !B
!(A || B) == !A && !B
 
Check Your Understanding     Check Your Understanding 
 
1.  
Which of the following is equivalent to 
!(A<0 || B<0)?
Correct
Not quite. Try again!
Not quite. Try again!
Not quite. Try again!