Answer:
The other side is 7.48 yards.
Step-by-step explanation:
Given that,
Hypotenuse = 15 yards
One leg = 13 yards
We need to find the length of the other leg. We can use the Pythagoras theorem to find it such that,

Where
h is other leg 
Put all the values,

So, the other side is 7.48 yards.
 
        
             
        
        
        
The two trains the same distance from Buffalo is 20
        
             
        
        
        
Answer:
It's fine. It is a function. The language can be very convoluted. Put simply a domain value cannot have 2 different range values.
Step-by-step explanation:
The confusing part I think, is probably the fact that -1 and 1 both have an answer of 5. 
That's fine. Parabolas do that and they are functions. Two different xs can have the same value. The thing that eliminates functions is when the x value (the domain) has two different y values (the range values). Then you don't have a function.
To try and make it clearer if 1 pointed at both 3 and 5 you would not have a function.