x 
1 
2 
3 
4 
n 
y 
4 
7 
10 
13 

Fill in the blank above. Write your answer in the form “an + b” where a and b are either positive or negative constants (or 0) .
The yvalue increases 3 for every 1 xvalue. Thus, we know that the first part of the equation is 3x.
Plugging 3x into the first column of the table, we have 3 (1) + b = 4. b must be equal to 1.
The pattern is y = 3x + 1, so the blank should be filled as “3n + 1,”