Question

Please help me with this!

Answer 1

Differences between x-values are 1. Differences between y-values are 2. The y-values are changing 2 times as fast as the x-values, so you are looking for an answer that involves 2x. The appropriate choice is
   D. 2x + 3

_____
You can check this result:
   for x=1: 2·1 + 3 = 5
   for x=4: 2·4 + 3 = 11
These values correspond to those in the table.

Answer 2

Let's just list the coordinats first.
(1,5)
(2,7)
(3,9)
(4,11)

When you see 3 and 9, you sometimes immediately think it is 3x=y, but you have to look at the other coordinates as well. This can be show in option a, 5x=y. This can not be the anser because 3×5=15≠9. We can eliminate that answer. Option B says that you are adding 2, but when you add 2 to 4, it equals 6 and not 11. The same for C, 4 added to 4 equals 8, not 11.

The one left, D, is the answer. When you put each x value in, you do get the corresponding y value as well. To even make sure, I made a graph with 2x+3=y as the function to see if those values/coordinates would pop up.