| $$ \begin{aligned}\frac{4x^2-16x+12}{x^2-9}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{4x-4}{x+3}\end{aligned} $$ | |
| ① | Simplify $ \dfrac{4x^2-16x+12}{x^2-9} $ to $ \dfrac{4x-4}{x+3} $. Factor both the denominator and the numerator, then cancel the common factor. $\color{blue}{x-3}$. $$ \begin{aligned} \frac{4x^2-16x+12}{x^2-9} & =\frac{ \left( 4x-4 \right) \cdot \color{blue}{ \left( x-3 \right) }}{ \left( x+3 \right) \cdot \color{blue}{ \left( x-3 \right) }} = \\[1ex] &= \frac{4x-4}{x+3} \end{aligned} $$ |