Step 1 :
After factoring out $ -3x^{2} $ we have:
$$ -3x^{4}-9x^{3}+15x^{2} = -3x^{2} ( x^{2}+3x-5 ) $$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:
$$ \color{blue}{ b = 3 } ~ \text{ and } ~ \color{red}{ c = -5 }$$Now we must discover two numbers that sum up to $ \color{blue}{ 3 } $ and multiply to $ \color{red}{ -5 } $.
Step 3: Find out pairs of numbers with a product of $\color{red}{ c = -5 }$.
PRODUCT = -5 | |
-1 5 | 1 -5 |
Step 4: Because none of these pairs will give us a sum of $ \color{blue}{ 3 }$, we conclude the polynomial cannot be factored.