| $$ \begin{aligned}0.2584x^2-4.3923x-1.8047& \xlongequal{ }0x^2-4x-1.8047 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-4x-1\end{aligned} $$ | |
| ① | Combine like terms: $$ -4x-1 = -4x-1 $$ |