Step 1 :
After factoring out $ 4 $ we have:
$$ 4x^{2}+36x-56 = 4 ( x^{2}+9x-14 ) $$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:
$$ \color{blue}{ b = 9 } ~ \text{ and } ~ \color{red}{ c = -14 }$$Now we must discover two numbers that sum up to $ \color{blue}{ 9 } $ and multiply to $ \color{red}{ -14 } $.
Step 3: Find out pairs of numbers with a product of $\color{red}{ c = -14 }$.
PRODUCT = -14 | |
-1 14 | 1 -14 |
-2 7 | 2 -7 |
Step 4: Because none of these pairs will give us a sum of $ \color{blue}{ 9 }$, we conclude the polynomial cannot be factored.