Tap the blue circles to see an explanation.
$$ \begin{aligned}(t+8)(t-8)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}t^2-8t+8t-64 \xlongequal{ } \\[1 em] & \xlongequal{ }t^2 -\cancel{8t}+ \cancel{8t}-64 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}t^2-64\end{aligned} $$ | |
① | Multiply each term of $ \left( \color{blue}{t+8}\right) $ by each term in $ \left( t-8\right) $. $$ \left( \color{blue}{t+8}\right) \cdot \left( t-8\right) = t^2 -\cancel{8t}+ \cancel{8t}-64 $$ |
② | Combine like terms: $$ t^2 \, \color{blue}{ -\cancel{8t}} \,+ \, \color{blue}{ \cancel{8t}} \,-64 = t^2-64 $$ |