8-2=6
180×6=1080 degrees
sum of interior angle of an octagonal box = 1080 degrees
        
                    
             
        
        
        
Answer:
6
Step-by-step explanation:
 
        
             
        
        
        
Answer:
(-2, 1)
Step-by-step explanation:
consider the following equations: -x-y=1 y=x+3 
For the lines to intersect, the  values must be the same
 -x-y=1
x + y = -1
y = -x - 1
Equating the y values 
-x - 1 = x+ 3
-x-x = 3 + 1
-2x = 4
x = 4/-2
x = -2
Substitute x = -2 into y = x+3
y = -2 + 3
y = 1
Hence the required coordinate is (-2, 1)