A train leaves the station at 9:00 pm traveling east at 36 miles per hour. A second train leaves the station at 10:00 pm traveling west at 42 miles per hour. At what time will both trains have traveled the same distance?

Answer: (D) 4, -3

Step-by-step explanation:

In order for the set of coordinates to be a function, there cannot be duplicate x-values. So, there cannot be the following: -4, 3, 4

A) x = 1   this CAN be in the set

B) x = -3  this CAN be in the set

C) x = 3 and y = 6   this is a duplicate of a coordinate already in the set.  You can plot this point and still pass the vertical line test

D) x = 4 and y = -3   this cannot be included in the set . It will create two different coordinates passing through x = 4 so will fail the vertical line test.

Answer:

C. (x, y) = (3, 6)

Step-by-step explanation: A function is when x's don't repeat.

The correct answer is C. (x, y) = (3, 6) because it would repeating the x's.

Here's Why:

{ (-4, 2), (3, 6), (4, 3), (x, y) }

If you substitute in (3, 6) for the last ordered pair, it would be repeating the number 3. So, (3, 6) can not be included in the set. But the ordered pairs that would NOT be repeating the x's, are these ordered pairs:

A. (x, y) = (1, 2)

B. (x, y) = (-3, 6)

D. (x, y) = (4, -3)

A, B, & D are ordered pairs that can make this set a function.

Hope this helps you!!! :)