If x represents any number in the first column witch expression can always be used to find the value of y in the second coloumn x 1 2 3 4 y 5 7 9 11

Set up an equation and solve, or find a common sequence.

We can set up an equation like so, using x = 1 as a base:

x(number) + (another number) = y

translate to:

1(x) + (number) = 5

The common difference is 2 for each y value, so let's use that as a multiplier:

1(2) + number = y
2 + x = 5
x = 3

So lets move up a step:
x = 2 and y = 7

We use 2 as our multiplier and 3 as our adder:
2(x) + 3 = y
2(2) + 3 = 7
4 + 3 = 7

Lets try one more case :
x = 4 and y = 11

2(4) + 3 = 11
8 + 3 = 11
11 = 11

Y=3x+1 so the first one