I need the answer to the bottom one not the top.
![I need the answer to the bottom one not the top class=](https://us-static.z-dn.net/files/d56/67654078173146e4bed8d70f8e77680c.png)
The difference bewteen an equation and an expression is the equal sign. An equation sets two things equal, while an expression expresses a value. This means that 3a + 9 is the expression.
Hope this helps!