Answer:
z = -1
Step-by-step explanation:
You must first start out by adding 19 to both sides to isolate the variable z, which results in:
2z = -2
Now, you can just divide by two on both sides to get z completely on its own, which gives you:
z = -1
Hope this helped somewhat! :D
 
        
             
        
        
        
Answer:
x=0
y=3
Step-by-step explanation:
2(x+3)=2x+6, substituting the first equation in the second
2x+6=2x+6, rearranging the equations
2x-2x=6-6
0=0
y=0+3
y=3
 
        
             
        
        
        
Answer:
-2 x (5x-12)
Step-by-step explanation:
 
        
             
        
        
        
Because the second derivative of the function at the point is negative, the graph must be concave down at this point. Because the first derivative indicates that the function is also likely to be a maximum or minimum, the point must be a maximum.
        
             
        
        
        
It will take 8 minutes.
You use a proportion 
5/1=2400/x you use 2400 because 2.4km=2400 meters and u need to use the same unit of measurement.
so cross multiplying gives you 5x=2400 which is equal to 480. BUT this is 48 seconds, and it asks you how many minutes, not seconds. So, you divide by 60 because there are 6 seconds in a minute, and you get 8.