Chapter 4 - Writing Linear Functions - 4.6 - Arithmetic Sequences - Exercises - Page 214: 11

$31,34$ and $37$.

Each term is $3$ more than the previous term. So, the common difference is $3$. Add $3$ to a term to find the next term. The next three terms are $28+3, 28+2(3)$ and $28+3(3)$. That is, $31,34$ and $37$.