Tap the blue circles to see an explanation.
| $$ \begin{aligned}x(1+3x+2x)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}x(5x+1) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}5x^2+x\end{aligned} $$ | |
| ① | Combine like terms: $$ 1+ \color{blue}{3x} + \color{blue}{2x} = \color{blue}{5x} +1 $$ |
| ② | Multiply $ \color{blue}{x} $ by $ \left( 5x+1\right) $ $$ \color{blue}{x} \cdot \left( 5x+1\right) = 5x^2+x $$ |