| $$ \begin{aligned}\frac{x^2+6x+8}{3x+12}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{x+2}{3}\end{aligned} $$ | |
| ① | Simplify $ \dfrac{x^2+6x+8}{3x+12} $ to $ \dfrac{x+2}{3} $. Factor both the denominator and the numerator, then cancel the common factor. $\color{blue}{x+4}$. $$ \begin{aligned} \frac{x^2+6x+8}{3x+12} & =\frac{ \left( x+2 \right) \cdot \color{blue}{ \left( x+4 \right) }}{ 3 \cdot \color{blue}{ \left( x+4 \right) }} = \\[1ex] &= \frac{x+2}{3} \end{aligned} $$ |