| $$ \begin{aligned}\frac{3b^2+5b-12}{9b^2+27b}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{3b-4}{9b}\end{aligned} $$ | |
| ① | Simplify $ \dfrac{3b^2+5b-12}{9b^2+27b} $ to $ \dfrac{3b-4}{9b} $. Factor both the denominator and the numerator, then cancel the common factor. $\color{blue}{b+3}$. $$ \begin{aligned} \frac{3b^2+5b-12}{9b^2+27b} & =\frac{ \left( 3b-4 \right) \cdot \color{blue}{ \left( b+3 \right) }}{ 9b \cdot \color{blue}{ \left( b+3 \right) }} = \\[1ex] &= \frac{3b-4}{9b} \end{aligned} $$ |