Answer:
1. The constant term is 16
![f(x) = {x}^(2) + 8x + 16 - 16- 15](https://img.qammunity.org/2021/formulas/mathematics/middle-school/xzwvwrmhnvsriq2k3rxz8w8c0shckaqk63.png)
2.
![f(x) =( {x}^(2) + 8x + 16 )- 16- 15](https://img.qammunity.org/2021/formulas/mathematics/middle-school/rzo78vhmqdbmq2lclhqc032yquicnhz175.png)
3.
![f(x) = {(x + 4)}^(2) - 31](https://img.qammunity.org/2021/formulas/mathematics/middle-school/3vujf8318bco0dn4125t3riu7lo3wg4jkp.png)
Explanation:
The given quadratic trinomial is
![f(x) = {x}^(2) + 8x - 15](https://img.qammunity.org/2021/formulas/mathematics/middle-school/ixlmnhze1b84aynberymlo0y7lbqdqbyuf.png)
The coefficient of x is 8. Half of 8 is 4.
The square of 4 is 16.
We add and subtract 16 to get;
![f(x) = {x}^(2) + 8x + 16 - 16- 15](https://img.qammunity.org/2021/formulas/mathematics/middle-school/xzwvwrmhnvsriq2k3rxz8w8c0shckaqk63.png)
The first three terms make a perfect square:
![f(x) =( {x}^(2) + 8x + 16 )- 16- 15](https://img.qammunity.org/2021/formulas/mathematics/middle-school/rzo78vhmqdbmq2lclhqc032yquicnhz175.png)
We now factor the perfect square and collect like terms to get:
![f(x) = {(x + 4)}^(2) - 31](https://img.qammunity.org/2021/formulas/mathematics/middle-school/3vujf8318bco0dn4125t3riu7lo3wg4jkp.png)
This is called the vertex form.