Code: Select all

```
3x + 21
-------------
3x+4) 9x^2 – 9x – 28
-9x^2 – 12x
-------------
- 21x – 28
- 63x + 84
-------------
84 – 112
```

This is at least the third time I have had this problem in the last page and a half. Can anyone see where I went wrong?