Tap the blue circles to see an explanation.
$$ \begin{aligned}(x+d)^2& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}x^2+2dx+d^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}d^2+2dx+x^2\end{aligned} $$ | |
① | Find $ \left(x+d\right)^2 $ using formula. $$ (A + B)^2 = \color{blue}{A^2} + 2 \cdot A \cdot B + \color{red}{B^2} $$where $ A = \color{blue}{ x } $ and $ B = \color{red}{ d }$. $$ \begin{aligned}\left(x+d\right)^2 = \color{blue}{x^2} +2 \cdot x \cdot d + \color{red}{d^2} = x^2+2dx+d^2\end{aligned} $$ |
② | Combine like terms: $$ d^2+2dx+x^2 = d^2+2dx+x^2 $$ |