Step 1 :
To factor $ x^{3}+1000 $ 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 = 10 $ , we have:
$$ x^{3}+1000 = ( x+10 ) ( x^{2}-10x+100 ) $$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:
$$ \color{blue}{ b = -10 } ~ \text{ and } ~ \color{red}{ c = 100 }$$Now we must discover two numbers that sum up to $ \color{blue}{ -10 } $ and multiply to $ \color{red}{ 100 } $.
Step 3: Find out pairs of numbers with a product of $\color{red}{ c = 100 }$.
| PRODUCT = 100 | |
| 1 100 | -1 -100 |
| 2 50 | -2 -50 |
| 4 25 | -4 -25 |
| 5 20 | -5 -20 |
| 10 10 | -10 -10 |
Step 4: Because none of these pairs will give us a sum of $ \color{blue}{ -10 }$, we conclude the polynomial cannot be factored.