Tap the blue circles to see an explanation.
| $$ \begin{aligned}(2x-5)(2x+5)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}4x^2+10x-10x-25 \xlongequal{ } \\[1 em] & \xlongequal{ }4x^2+ \cancel{10x} -\cancel{10x}-25 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}4x^2-25\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{2x-5}\right) $ by each term in $ \left( 2x+5\right) $. $$ \left( \color{blue}{2x-5}\right) \cdot \left( 2x+5\right) = 4x^2+ \cancel{10x} -\cancel{10x}-25 $$ |
| ② | Combine like terms: $$ 4x^2+ \, \color{blue}{ \cancel{10x}} \, \, \color{blue}{ -\cancel{10x}} \,-25 = 4x^2-25 $$ |