Step 1 :
To factor $ x^{3}+512 $ we can use sum of cubes formula:
$$ I^3 - II^3 = (I + II)(I^2 - I \cdot II + II^2) $$After putting $ I = x $ and $ II = 8 $ , we have:
$$ x^{3}+512 = ( x+8 ) ( x^{2}-8x+64 ) $$Step 2 :
Step 2: 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:
$$ \color{blue}{ b = -8 } ~ \text{ and } ~ \color{red}{ c = 64 }$$Now we must discover two numbers that sum up to $ \color{blue}{ -8 } $ and multiply to $ \color{red}{ 64 } $.
Step 3: Find out pairs of numbers with a product of $\color{red}{ c = 64 }$.
| PRODUCT = 64 | |
| 1 64 | -1 -64 |
| 2 32 | -2 -32 |
| 4 16 | -4 -16 |
| 8 8 | -8 -8 |
Step 4: Because none of these pairs will give us a sum of $ \color{blue}{ -8 }$, we conclude the polynomial cannot be factored.