Tap the blue circles to see an explanation.
$$ \begin{aligned}(5+i)(-x)^2& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}(5+i)\cdot1x^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}5x^2+ix^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}ix^2+5x^2\end{aligned} $$ | |
① | $$ \left( -x \right)^2 = (-1)^2x^2 = x^2 $$ |
② | $$ \left( \color{blue}{5+i}\right) \cdot x^2 = 5x^2+ix^2 $$ |
③ | Combine like terms: $$ ix^2+5x^2 = ix^2+5x^2 $$ |