It seems that $ z^{2}+30z+255 $ cannot be factored out.
Step 1: Identify constants $ \color{blue}{ b }$ and $\color{red}{ c }$. ( $ \color{blue}{ b }$ is a number in front of the $ x $ term and $ \color{red}{ c } $ is a constant). In our case:
$$ \color{blue}{ b = 30 } ~ \text{ and } ~ \color{red}{ c = 255 }$$Now we must discover two numbers that sum up to $ \color{blue}{ 30 } $ and multiply to $ \color{red}{ 255 } $.
Step 2: Find out pairs of numbers with a product of $\color{red}{ c = 255 }$.
PRODUCT = 255 | |
1 255 | -1 -255 |
3 85 | -3 -85 |
5 51 | -5 -51 |
15 17 | -15 -17 |
Step 3: Because none of these pairs will give us a sum of $ \color{blue}{ 30 }$, we conclude the polynomial cannot be factored.