| $$ \begin{aligned}\frac{20x^2+30x}{4x^3+6x^3}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{20x^2+30x}{10x^3}\end{aligned} $$ | |
| ① | Simplify denominator $$ \color{blue}{4x^3} + \color{blue}{6x^3} = \color{blue}{10x^3} $$ |