What would the rule be?

2 → 6

                           <----  There is a gap here; it could be filled with 3 → 13

4 → 20

5 → 27

6 → 34

7 → 41

 Starting with 4 → 20, notice that the x's are increasing by 1 and the y's are increasing by 7.

This means that the slope of the equation (which is the change in y divided by the cahnge in x) is  7/1  or just 7

 

The equation will then be;  y  =  7x + b

To find the value of b, replace the x and the y with any of the pairs;

choosing  (4, 20)      --->     20  =  7(4) + b

                                            20  =  28 + b

                                             -8  =  b

 

Equation:  y  =  7x - 8