5*2400=$12,000 is the total costs for 5 decks costing $2,400 each.
Replace x in the equations and see which one gets the matching y :
-5(0) = 0 +1 = 1
-5(1) = -5 + 1 = -4
-5(-1) = 5 +6 = 6
The first equation works.
Answer:
The first set of ordered pairs is a function, because no two ordered pairs have the same first coordinates with different second coordinates. The second example is not a function, because it contains the ordered pairs (1,2) and (1,5). These have the same first coordinate and different second coordinates.
Please ask the question in English, if you are not able to, I believe you are in the wrong language section and suggest you try something else before you get your question taken down.
