Question

What is the solution set of {x<-4}∩{x|x>9}

Answer 1

The cup symbol means that these two sets intersect.
This way, the solution would be the intersection of
x<-4 and x>9 (if such exists).

Answer 2

Is there a number that is simultaneously smaller than -4 and greater than 9??

Answer 3

Do you think an intersection of this exists?