Tap the blue circles to see an explanation.
$$ \begin{aligned}x(2x+7)+x\cdot(9+5x)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}2x^2+7x+9x+5x^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}7x^2+16x\end{aligned} $$ | |
① | Multiply $ \color{blue}{x} $ by $ \left( 2x+7\right) $ $$ \color{blue}{x} \cdot \left( 2x+7\right) = 2x^2+7x $$Multiply $ \color{blue}{x} $ by $ \left( 9+5x\right) $ $$ \color{blue}{x} \cdot \left( 9+5x\right) = 9x+5x^2 $$ |
② | Combine like terms: $$ \color{blue}{2x^2} + \color{red}{7x} + \color{red}{9x} + \color{blue}{5x^2} = \color{blue}{7x^2} + \color{red}{16x} $$ |