Question 175274
We need to look for a pattern.  Notice that as the amount of pasta goes up a cup, the length of time needed to boil goes up by 1 1/2 minutes.  Thus, for example, 4 cups of pasta takes 7 1/2 minutes, 5 cups of pasta takes 9 minutes, 6 cups of pasta takes 10 1/2 minutes, and therefore 7 cups of pasta takes 12 minutes.  So there is your pattern.  

For the optional part:  How can we write an expression to represent this pattern?  As noted above, for each increase in cups of pasta, there is a 1 1/2 minutes increase in time needed to boil.  Hopefully with the pattern noted, you can work on figuring out the answer to this part.