For your answer the will be shown below 
Unit rate= 9
        
                    
             
        
        
        
The discriminant is b<span>²-4ac
We can rewrite x</span>² = 4 to x<span>² + 0x - 4 = 0
So a = 1, b = 0, c = -4
</span>Δ = 0 - 4 * 1 * -4
Δ = 16
The answer is B
        
                    
             
        
        
        
Answer:
Original number is 47
Step-by-step explanation:
Given: The tens digit is three less than the units digit. If the digits are reversed, the sum of the reversed number and the original number is 121.
To find: the original number
Solution:
Let x denotes digit at ones place.
As the tens digit is three less than the units digit,
Digit at tens place = 
Original number = 
When digits are reversed,
Reversed number = 
As the sum of the reversed number and the original number is 121,

So,
original number = 
 
        
             
        
        
        
Answer:
x = 4, -2 1/2
Step-by-step explanation:
factors:
(2x + 5) (x - 4)
set each factor equal to zero:
2x + 5 = 0
2x = -5
x = -5/2
x - 4 = 0
x = 4
 
        
             
        
        
        
Answer: Santa's speed in still air is 6 miles per minute
Speed of the wind is 1 mile per minute
Step-by-step explanation:
Let x represent the speed of Santa in still air. It is assumed that in still air. She is flying with the wind. If the speed of the wind is y, then him total speed is x + y
It takes Santa 5 minutes to fly 35 miles with the wind. 
Speed = distance / time
It means that 
x + y = 35/5 = 7
It takes him 7 minutes to fly 35 miles against the wind. This means that his total speed will be x - y
Speed = distance/time. Therefore,
x - y = 35 /5 = 5 - - - - - - 1
Substituting x = 7 - y into equation 1, it becomes
7 - y - y = 5
-2y = 5 - 7 = -2
y = -2/-2 = 1
x = 7 - y = 7 - 1
x = 6