Velocity of the ring wraiths relative to the air:

The speed  is what we want to find - this is the speed at which the wraiths are flying in the air.
 is what we want to find - this is the speed at which the wraiths are flying in the air.
(Note:  denotes velocity, while
 denotes velocity, while  denotes speed)
 denotes speed)
Velocity of air relative to the ground:

The ring wraiths want their trajectory to be due north, which means their velocity relative to the ground should be

To an observer on the ground,  is the speed at which the wraiths would appear to be moving in the air.
 is the speed at which the wraiths would appear to be moving in the air.
The relative velocities satisify



 
        
             
        
        
        
Thanks for the free points! Have a fantastic day!
        
                    
             
        
        
        
Answer:
C. 40-4x-12x^2
Step-by-step explanation:
very simple
? – (20 – 4x – 5x2) = 20 – 7x2, so ?  = 20 – 7x2 + (20 – 4x – 5x2)
?  = 20 – 7x2 + (20 – 4x – 5x2)=20-7x²+20-4x-5x²=40-12x²-4x
 
        
                    
             
        
        
        
Answer:
25
Step-by-step explanation:
Well, we need to simplify this. we have a ratio of 80:125.
As these numbers end in either 0 or 5, we know they are divisible by 5.
By dividing these by five, our ratio becomes 16:25.
As we have 16 jackets, we know we must need to sell 25 jackets to maintain the ratio.