Step 1 :
After factoring out $ x $ we have:
$$ x^{3}+9x^{2}-52x = x ( x^{2}+9x-52 ) $$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:
$$ \color{blue}{ b = 9 } ~ \text{ and } ~ \color{red}{ c = -52 }$$Now we must discover two numbers that sum up to $ \color{blue}{ 9 } $ and multiply to $ \color{red}{ -52 } $.
Step 3: Find out pairs of numbers with a product of $\color{red}{ c = -52 }$.
PRODUCT = -52 | |
-1 52 | 1 -52 |
-2 26 | 2 -26 |
-4 13 | 4 -13 |
Step 4: Find out which pair sums up to $\color{blue}{ b = 9 }$
PRODUCT = -52 and SUM = 9 | |
-1 52 | 1 -52 |
-2 26 | 2 -26 |
-4 13 | 4 -13 |
Step 5: Put -4 and 13 into placeholders to get factored form.
$$ \begin{aligned} x^{2}+9x-52 & = (x + \color{orangered}{\square} )(x + \color{orangered}{\square}) \\ x^{2}+9x-52 & = (x -4)(x + 13) \end{aligned} $$