Tap the blue circles to see an explanation.
| $$ \begin{aligned}(x+a)^3& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}x^3+3ax^2+3a^2x+a^3 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}a^3+3a^2x+3ax^2+x^3\end{aligned} $$ | |
| ① | Find $ \left(x+a\right)^3 $ using formula $$ (A + B) = A^3 + 3A^2B + 3AB^2 + B^3 $$where $ A = x $ and $ B = a $. $$ \left(x+a\right)^3 = x^3+3 \cdot x^2 \cdot a + 3 \cdot x \cdot a^2+a^3 = x^3+3ax^2+3a^2x+a^3 $$ |
| ② | Combine like terms: $$ a^3+3a^2x+3ax^2+x^3 = a^3+3a^2x+3ax^2+x^3 $$ |