Table:
x c(x)
(days) (dollars)
1. 25
2. 45
3. 60
4. 70

2) Yes, each x-coordinate is only used once.

3) {1,2,3,4}

4) {25,45,60,70}

5) (3,60)

6) No because (4,7) and (4,25) share the same x-coordinate.

Step-by-step explanation:

A relation is a function if there is no more than one y-value assigned to an x.

Any x used can only be used once in an order pair.

You that here.

(1,25)

(2,45)

(3,60)

(4,70)

So basically because all of the x-coordinates are different, this is a function.

The domain is the x-coordinate of each pair (the first of each pair):

{1,2,3,4}.

The range is the y-coordinate of each pair (the second number of each pair):

{25,45,60,70}.

One ordered pair that I see in the table is (3,60). There are 3 others you can choose and I named them above.

{(4,10),(3,15),(1,5),(2,25),(4,25)} is not a function because there are more than one pairs with the same x-coordinate,4.  

n=9

step-by-step explanation:

7 times a number = 7n

decreased by 13 = 7n-13

same as is =

5 times the number = 5n

increased by 5 = 5n+5

7n-13 = 5n+5

2n=18

n=9