Tap the blue circles to see an explanation.
| $$ \begin{aligned}(4-x)^3& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}64-48x+12x^2-x^3 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-x^3+12x^2-48x+64\end{aligned} $$ | |
| ① | Find $ \left(4-x\right)^3 $ using formula $$ (A - B) = A^3 - 3A^2B + 3AB^2 - B^3 $$where $ A = 4 $ and $ B = x $. $$ \left(4-x\right)^3 = 4^3-3 \cdot 4^2 \cdot x + 3 \cdot 4 \cdot x^2-x^3 = 64-48x+12x^2-x^3 $$ |
| ② | Combine like terms: $$ -x^3+12x^2-48x+64 = -x^3+12x^2-48x+64 $$ |