Tap the blue circles to see an explanation.
| $$ \begin{aligned}(2x-3)(2x+3)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}4x^2+6x-6x-9 \xlongequal{ } \\[1 em] & \xlongequal{ }4x^2+ \cancel{6x} -\cancel{6x}-9 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}4x^2-9\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{2x-3}\right) $ by each term in $ \left( 2x+3\right) $. $$ \left( \color{blue}{2x-3}\right) \cdot \left( 2x+3\right) = 4x^2+ \cancel{6x} -\cancel{6x}-9 $$ |
| ② | Combine like terms: $$ 4x^2+ \, \color{blue}{ \cancel{6x}} \, \, \color{blue}{ -\cancel{6x}} \,-9 = 4x^2-9 $$ |