Answer:
Step-by-step explanation:
hello : 
19=3s+4
19-4 = 3s+4-4
3s=15
s=15/3
s=5
 
        
                    
             
        
        
        
surface area= perimeter x height + 2b 
s= pxh+2b 
example: 18(8)+2(12)
explain:  18 is the perimeter and 8 is the height then you have to add the base times 2 
 
        
             
        
        
        
The chance is 50% because if there are 2 children the probability would be 1/2 or 50%.
        
             
        
        
        
Answer:
-9x + 13
Step-by-step explanation:
9 -3x +(-6x) +4
you will add -3x+(-6x), then add 9+4
-3x+(-6x) = -9x   (a negative pus and negative = a negative
9 +4 = 13
-9x + 13