Definition 1: A relation is any subset of a Cartesian product. For instance, a subset of  , called a "binary relation from A to B," is a collection of ordered pairs (a,b) with first components from A and second components from B, and, in particular, a subset of
, called a "binary relation from A to B," is a collection of ordered pairs (a,b) with first components from A and second components from B, and, in particular, a subset of  is called a "relation on A."
 is called a "relation on A." 
Definition 2: A function is a relation that associates each element x of a set X to a single element y of another set Y (possibly the same set). A function is uniquely represented by its graph which is the set of all ordered pairs (x, f (x)).
From these definitions you can see that every function is a relation from X to Y, but not via versa (because you can consider relation  - here for one x exist two y).
 - here for one x exist two y).
Answer: Correct choice is B.
 
        
                    
             
        
        
        
Answer:
15 yd = 45 ft because :
Step-by-step explanation:
You have to multiply the length by 3. 
1 yd = 3 ft. 
15 x 3 = 45. 
Hope this helps,
Davinia.
 
        
             
        
        
        
We have : 
s - 39⁰+ s - 9⁰ = s + 29⁰ 
s + s - s = 29⁰ + 9⁰ + 39⁰
s = 77⁰
Answer: 77⁰
Ok done. Thank to me :>