Tap the blue circles to see an explanation.
| $$ \begin{aligned}(y-5x)^3& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}y^3-15xy^2+75x^2y-125x^3 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-125x^3+75x^2y-15xy^2+y^3\end{aligned} $$ | |
| ① | Find $ \left(y-5x\right)^3 $ using formula $$ (A - B) = A^3 - 3A^2B + 3AB^2 - B^3 $$where $ A = y $ and $ B = 5x $. $$ \left(y-5x\right)^3 = y^3-3 \cdot y^2 \cdot 5x + 3 \cdot y \cdot \left( 5x \right)^2-\left( 5x \right)^3 = y^3-15xy^2+75x^2y-125x^3 $$ |
| ② | Combine like terms: $$ -125x^3+75x^2y-15xy^2+y^3 = -125x^3+75x^2y-15xy^2+y^3 $$ |