$$ \begin{aligned}\frac{a-1}{3a-3}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{1}{3}\end{aligned} $$ | |
① | Factor both the denominator and the numerator, then cancel the common factor. $\color{blue}{a-1}$. $$ \begin{aligned} \frac{a-1}{3a-3} & =\frac{ 1 \cdot \color{blue}{ \left( a-1 \right) }}{ 3 \cdot \color{blue}{ \left( a-1 \right) }} = \\[1ex] &= \frac{1}{3} \end{aligned} $$ |