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