| $$ \begin{aligned}\frac{x-5}{x^2-10x+25}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{1}{x-5}\end{aligned} $$ | |
| ① | Simplify $ \dfrac{x-5}{x^2-10x+25} $ to $ \dfrac{1}{x-5} $. Factor both the denominator and the numerator, then cancel the common factor. $\color{blue}{x-5}$. $$ \begin{aligned} \frac{x-5}{x^2-10x+25} & =\frac{ 1 \cdot \color{blue}{ \left( x-5 \right) }}{ \left( x-5 \right) \cdot \color{blue}{ \left( x-5 \right) }} = \\[1ex] &= \frac{1}{x-5} \end{aligned} $$ |