Answer:
26 because 30-4=26
Step-by-step explanation:
 
        
             
        
        
        
-31 because if you do p.e.m.d .a .s
        
             
        
        
        
Answer:
Quadrilateral as it is a four-sided ploygon, having 4 edges and corners
 
        
             
        
        
        
Answer:
Johnny is wrong.

Step-by-step explanation:
Johnny is wrong.
A better definition would be:  is the set of all elements that belong to at least one A or B.
 is the set of all elements that belong to at least one A or B.
So, the elements that belong to both A and B, like c and d in this exercise, also belong to  .
.
So:

 
        
             
        
        
        
3000 is the freaking right answer