Tap the blue circles to see an explanation.
$$ \begin{aligned}3x\cdot2-3x+9-5x\cdot2-8x-7& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}6x-3x+9-10x-8x-7 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}3x+9-18x-7 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}-15x+2\end{aligned} $$ | |
① | $$ 3 x \cdot 2 = 6 x $$$$ 5 x \cdot 2 = 10 x $$ |
② | Combine like terms: $$ \color{blue}{6x} \color{blue}{-3x} +9 = \color{blue}{3x} +9 $$Combine like terms: $$ \color{blue}{-10x} \color{blue}{-8x} -7 = \color{blue}{-18x} -7 $$ |
③ | Combine like terms: $$ \color{blue}{3x} + \color{red}{9} \color{blue}{-18x} \color{red}{-7} = \color{blue}{-15x} + \color{red}{2} $$ |