For all real numbers, if two numbers are equal to the same number, then they are equal to each other.

This property can be used together with other Properties of Equality to solve equations. $\begin{gathered} \begin{cases} x = {\color{#0000FF}{5y-30}} \\ {\color{#0000FF}{5y-30}} = 20 \end{cases} \quad \Rightarrow \quad \begin{aligned} x &=20 \end{aligned} \end{gathered}$ The Transitive Property of Equality also holds true if $a,$ $b,$ and $c$ are complex numbers.