$$ \begin{aligned}(6x-7y)^2& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}36x^2-84xy+49y^2\end{aligned} $$ | |
① | Find $ \left(6x-7y\right)^2 $ using formula. $$ (A - B)^2 = \color{blue}{A^2} - 2 \cdot A \cdot B + \color{red}{B^2} $$where $ A = \color{blue}{ 6x } $ and $ B = \color{red}{ 7y }$. $$ \begin{aligned}\left(6x-7y\right)^2 = \color{blue}{\left( 6x \right)^2} -2 \cdot 6x \cdot 7y + \color{red}{\left( 7y \right)^2} = 36x^2-84xy+49y^2\end{aligned} $$ |