$$ \begin{aligned}(x^2+2)^3& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}x^6+6x^4+12x^2+8\end{aligned} $$ | |
① | Find $ \left(x^2+2\right)^3 $ using formula $$ (A + B) = A^3 + 3A^2B + 3AB^2 + B^3 $$where $ A = x^2 $ and $ B = 2 $. $$ \left(x^2+2\right)^3 = \left( x^2 \right)^3+3 \cdot \left( x^2 \right)^2 \cdot 2 + 3 \cdot x^2 \cdot 2^2+2^3 = x^6+6x^4+12x^2+8 $$ |