Answer: There are 8 pepperoni pizzas she order.
Explanation:
Since we have given that
Number of vegetable pizzas and pepperoni pizzas for the eighth grade party = 51
Let the number of pepperoni pizzas be 'p'.
Let the number of vegetable pizzas be 'v'.
According to question,
![v=5p+3](https://img.qammunity.org/2019/formulas/mathematics/middle-school/eo73v03xmrco6qyi0d9199x8zved44zttt.png)
So, it becomes,
![v+p=51\\\\5p+3+p=51\\\\6p+3=51\\\\6p=51-3\\\\6p=48\\\\p=(48)/(6)\\\\p=8](https://img.qammunity.org/2019/formulas/mathematics/middle-school/qdh1x9szb2x0zinjrllhctip41am36om0e.png)
Hence, there are 8 pepperoni pizzas she order.