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