Answer: The range is 16 :)
Step-by-step explanation:
The lowest number is -9 and the highest is 7. the difference between those is 16. 
 
        
             
        
        
        
Based on the given mathematical statement, it can be rewritten into a mathematical equation to simplify and to be solved easily. The statement, "When one is subtracted from three-tenths of a number" corresponds to the equation, 3x/10 - 1, that is assuming the number is represented by the variable x. This is equal to one-fifth of the number. In other words,
3x/10 - 1 = x/5
x = 10
        
             
        
        
        
If point A is the midpoint then that means line segments XA and AY are equivalent so you can set:
3x=5x-6
(now you solve for x)
2x=6
(divide by 2 on both sides)
x=3
So BASICALLY,
XA= 3x= 3(3) = 9
AY= 5x-6= 5(3)-6 =9
So now you know the length of both sides, add those together and you get 
XY=18
        
             
        
        
        
<span>The definition of quadratic function is given by:
</span>

<span>
So the problem asks for two conditions:
<em>1. Write the quadratic function in factored form.
</em>
<em>2. The vertex has an x-coordinate of 3.</em>
Then the equation (1) must be written as follows:
</span>

<span>
To satisfy the two conditions:
 
So we are free to choose the value of one root, say:

Thus:
 
Finally, 
the answer is:

The graph of this function is shown in the figure below.</span>