| $$ \begin{aligned}\frac{10x^2+19x-15}{4x+10}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{5x-3}{2}\end{aligned} $$ | |
| ① | Simplify $ \dfrac{10x^2+19x-15}{4x+10} $ to $ \dfrac{5x-3}{2} $. Factor both the denominator and the numerator, then cancel the common factor. $\color{blue}{2x+5}$. $$ \begin{aligned} \frac{10x^2+19x-15}{4x+10} & =\frac{ \left( 5x-3 \right) \cdot \color{blue}{ \left( 2x+5 \right) }}{ 2 \cdot \color{blue}{ \left( 2x+5 \right) }} = \\[1ex] &= \frac{5x-3}{2} \end{aligned} $$ |