Step 1: 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:
$$ \color{blue}{ b = 14 } ~ \text{ and } ~ \color{red}{ c = 40 }$$Now we must discover two numbers that sum up to $ \color{blue}{ 14 } $ and multiply to $ \color{red}{ 40 } $.
Step 2: Find out pairs of numbers with a product of $\color{red}{ c = 40 }$.
PRODUCT = 40 | |
1 40 | -1 -40 |
2 20 | -2 -20 |
4 10 | -4 -10 |
5 8 | -5 -8 |
Step 3: Find out which pair sums up to $\color{blue}{ b = 14 }$
PRODUCT = 40 and SUM = 14 | |
1 40 | -1 -40 |
2 20 | -2 -20 |
4 10 | -4 -10 |
5 8 | -5 -8 |
Step 4: Put 4 and 10 into placeholders to get factored form.
$$ \begin{aligned} y^{2}+14y+40 & = (x + \color{orangered}{\square} )(x + \color{orangered}{\square}) \\ y^{2}+14y+40 & = (x + 4)(x + 10) \end{aligned} $$