Hello!
It looks like you meant,
[tex]z^2+17z+72[/tex]
Break the expression into two groups, that would imply splitting the 17.
[tex]=\left(z^2+8z\right)+\left(9z+72\right)[/tex]
Let's start factoring.
First, factor the [tex]z[/tex] from [tex]z^2+8z[/tex]
Then, factor the [tex]9[/tex] from [tex]9z+72[/tex]
We would be left with,
[tex]=z\left(z+8\right)+9\left(z+8\right)[/tex]
Factor out the common term, which is [tex](z+8)[/tex]
[tex]=\left(z+8\right)\left(z+9\right)[/tex]
Our final answer would be,
[tex]=\left(z+8\right)\left(z+9\right)[/tex]
You can feel free to let me know if you have any questions regarding this!
Thanks!
- TetraFish
