Solve $\color{blue}{x^2-3x+2 = 0}$ using factoring.
First we need to factor trinomial $ \color{blue}{ x^2-3x+2 } $ and than we use factored form to solve an equation $ \color{blue}{ x^2-3x+2 = 0} $.
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:
$$ \color{blue}{ b = -3 } ~ \text{ and } ~ \color{red}{ c = 2 }$$Now we must discover two numbers that sum up to $ \color{blue}{ -3 } $ and multiply to $ \color{red}{ 2 } $.
Step 2: Find out pairs of numbers with a product of $\color{red}{ c = 2 }$.
PRODUCT = 2 | |
1 2 | -1 -2 |
Step 3: Find out which pair sums up to $\color{blue}{ b = -3 }$
PRODUCT = 2 and SUM = -3 | |
1 2 | -1 -2 |
Step 4: Put -1 and -2 into placeholders to get factored form.
$$ \begin{aligned} x^{2}-3x+2 & = (x + \color{orangered}{\square} )(x + \color{orangered}{\square}) \\ x^{2}-3x+2 & = (x -1)(x -2) \end{aligned} $$Step 5: Set each factor to zero and solve equations.
$$ \begin{array}{ccc} \begin{aligned} x-1 &= 0 \\ x &= 1 \end{aligned} & ~ & \begin{aligned} x-2 &= 0 \\ x &= 2 \end{aligned} \end{array} $$